A narrow pelvis during pregnancy: degrees, the course of childbirth. Narrowing of the pelvis

About 5% of expectant mothers face this problem. A narrow pelvis during pregnancy often causes complications during childbirth. And also this is one of the indications for a cesarean section. Distinguish between small and large pelvis. The uterus is located in the pelvic area. If its wings do not spread, the abdomen takes on a pointed shape. This is because the uterus moves forward. In progress generic activity the child moves along the small pelvis. And if it is insufficient in size, this becomes a serious obstacle to the advancement of the fetus and a favorable outcome of childbirth. Consider the varieties and features of bearing a child with a narrow pelvis.

Distinguish between anatomically and clinically narrow pelvis. The first type is diagnosed when the size deviates from the norm by 1.5-2 cm.The anatomical shape, in turn, is divided into several groups:

• flat;
• generally evenly narrowed;
• transversely narrowed.

It is rather problematic to prevent the formation of this deviation. The reasons for its development include:

• infectious diseases;
• hormonal imbalance during puberty;
• nutritional deficiencies;
• damage bone tissue due to rickets, tuberculosis or poliomyelitis;
• great physical activity during the formation of the skeletal system.

A clinically narrow pelvis is a condition in which there is a discrepancy between the size of the fetal head and the mother's pelvis. Such a deviation cannot be predicted and can only be determined during labor. In some cases, women find out about the presence of this complication after childbirth. It can even develop in expectant mothers who have not encountered the problem of a narrow pelvis during the entire period of pregnancy.

The clinically narrow pelvis is subdivided into 3 types depending on the degree of discrepancy:

• relative inconsistency;
• significant discrepancy;
• absolute discrepancy.

Determination of the degree is carried out on the basis of such features as the peculiarity of the placement of the head, the absence or presence of its movement, as well as the configurational feature. The reasons for this deviation are:

• large fruit sizes, which can vary from 4 to 5 kg;
• anatomically narrow pelvis;
• overburdening, in which the head loses the ability to configure;
• tumor formations in the small pelvis;
• extensor presentation, when the head is inserted into the entrance in an extended state;
• pathologies of fetal development, which are characterized by an increase in the size of the head.

Narrowing degrees

1. A narrow pelvis of 1 degree during pregnancy is a phenomenon that is not an absolute indication for a cesarean section. In this case, delivery by this method is carried out in the presence of concomitant complications. This is a breech presentation or an abnormal position of the fetus, its large size, a scar on the uterus.
2. Natural delivery at grade 2 can lead to various complications. Therefore, in this situation, in most cases, a cesarean section is performed. An exception may be childbirth during a premature pregnancy, when the fetus is small and can pass through a narrow pelvis.
3. At 3 and 4 degrees, natural delivery is impossible, and a cesarean section is performed to extract the child. This is the only solution for complications such as deformational changes in the small pelvis or bone tumors, the presence of which creates an obstacle to the child's progress through the birth canal.

A narrow pelvis during pregnancy: how to determine

This problem is diagnosed using the following methods:

• evaluating the shape of the abdomen. In primiparous, it has a pointed appearance, in women giving birth again, it is saggy;
• establishment of anamnesis;
• measuring the mass and height of a woman;
• measurement with a tazometer;
• ultrasound diagnostics;
• radiography. But this method is used only if the above methods did not give the necessary results and the situation remains uncertain. X-rays give an idea of ​​the size of the mother's pelvis and the baby's head. When measuring, the size is determined, which corresponds to the entrance to the small pelvis.

Using a pelvis meter, the doctor determines the distance between the greater trochanters of the thigh bones (the norm is 30 cm or more), the anterior spines ( normal rate- over 25 cm), iliac ridges (28 cm and more). The outer and true conjugate is also measured. The first indicator is determined from the upper point of the pubic symphysis to the supra-sacral fossa and should normally be 20 cm.To measure the true conjugate, a vaginal examination is performed, during which the distance from the upper part of the sacral bone to the pubic articulation is determined.

Measurement methods also include the determination of the Michaelis rhombus. Inspection is carried out in a standing position. In the lumbosacral area, you can see a rhomboid figure, the corners of which are located on the sides, above the coccyx and in the lumbar region along the central line. The rhombus resembles a flat area over the sacrum bone. Its length in the longitudinal direction should normally be 11, and in the transverse direction - 10 cm. A decrease in these indicators and an asymmetric shape indicates an abnormal structure of the pelvis.

The bones of some women are quite massive. In this case, with a narrow pelvis, the examination results may correspond to the norm. The Soloviev index, which provides for the measurement of the circumference of the wrist, will help to get an idea of ​​the thickness of the bones. It should not exceed 14 cm.

Pregnancy, childbirth with a narrow pelvis

A narrow pelvis does not affect the bearing of a child. But a woman must be under the close supervision of specialists. During the last trimester, the fetus may take the wrong position, which provokes shortness of breath in the expectant mother. Due to the occurrence possible complications during childbirth, women with a narrow pelvis are at risk. Pre-hospitalization is recommended for them. Specialists, carrying out careful observation, will help prevent overmaturity, conduct an additional examination to clarify the degree of narrowing and the shape of the pelvis, and develop the most optimal delivery tactics.

A favorable course of labor with an anatomically narrow pelvis is possible if the baby's head is of medium size, and the process itself is quite active. Under other circumstances, certain complications arise. One of them is premature effusion amniotic fluid... Due to the narrowness of the pelvis, the child is not able to take the desired position. Its head does not fit into the pelvic region, but is located high above the entrance. As a result, the amniotic fluid is not divided into posterior and anterior, which occurs during the normal course of labor.

With the outflow of amniotic fluid, the baby's limbs or the umbilical cord can fall out. In this situation, attempts are made to fill the parts that have fallen out behind the head. If this cannot be done, then the volume of the pelvis, which is already small in size, decreases. This becomes an additional obstacle to the extraction of the fetus. If the loop falls out, it can press against the pelvic wall, which will limit the access of oxygen to the child and lead to his death. Umbilical cord prolapse should be considered a direct indication for caesarean section.

The high position of the head and the mobility of the uterus become the reasons for an incorrect presentation of the child, which can take a pelvic, oblique or transverse position. And also leads to the extension of the head. With a favorable delivery, she stays in a flexed state, first the occipital part appears. When unbending, a face is initially born.

Early rupture of amniotic fluid and the high position of the head become the reasons for the slow dilatation of the cervix, excessive stretching of its lower part, and weak labor. In women giving birth for the first time, weakness develops as a result of a prolonged labor process with a narrow pelvis. Multiparous people face complications such as excessive stretching of the uterine muscles. A prolonged course of labor and a prolonged anhydrous period often lead to the penetration of infection into the body of the fetus and the woman. The pathogenic microflora enters the uterine cavity from the vagina.

Oxygen starvation of the fetus is also a complication. With contractions and attempts, the bones of the head in the fontanel area go over each other, and it decreases. This causes the excitation of the nerve centers of the heart regulation of the child, the heartbeat is disturbed, which, against the background of short uterine contractions, leads to oxygen deficiency. If at the same time there is a deviation in the placental-uterine circulation, hypoxia becomes more pronounced. Such births are characterized by a long course. A child experiencing an oxygen deficiency during birth often has impaired blood flow in the brain, asphyxia, and trauma to the skull and back. Such children in the future need careful supervision by specialists and in rehabilitation.

The soft tissues in the birth canal area are compressed between the baby's head and the pelvic bones. This is due to the long stay of the head in one place. Pressure is also placed on the vagina, cervix, rectum and bladder, which interferes with blood circulation in these organs and causes them to swell. Difficulty moving the head makes the contractions more intense and painful. Often this leads to severe stretching of the lower uterine wall, which increases the likelihood of uterine rupture.

Due to deviations in the size of the narrow pelvis during pregnancy, the head deviates excessively towards the perineum. Since the tissues in this area are stretched, a dissection is required. Otherwise, it will not be possible to avoid the gap. Such a difficult course of labor makes it difficult for the uterus to contract, which leads to bleeding in postpartum period.

During childbirth, a certain amount of time is allotted to wait for the lowering of the head. In primiparous, this period is 1-1.5 hours, in multiparous - up to 60 minutes. If a clinically narrow pelvis is observed, waiting is not practiced, but a decision is made immediately about delivery by caesarean section. This situation occurs if the cervix is ​​completely open, and the head does not pass through the birth canal.

In the first and second stages of labor, an anatomical and functional assessment of the pelvis is carried out. The doctor determines its shape and degree of narrowing. Functional assessment is not always done. This procedure is discarded if, due to the incorrectly inserted head, the impossibility of delivery in a natural way is evident.

The integrity of the fetal bladder must be maintained for as long as possible. To do this, a woman must comply with bed rest, and when taking a recumbent position, lie on the side towards which the baby's head or back is directed. This will help lower the amniotic fluid and help keep it for as long as necessary. After the amniotic fluid has been drained, the vagina is examined regularly. This is necessary for the timely detection of small parts of the fetus or the umbilical cord and to assess the functional capacity of the pelvis.

In the course of labor, the contraction of the uterus and the condition of the child are monitored continuously with the help of cardiotocographs. The woman is injected medications that help improve blood flow in the uterus and placenta. To prevent the development of weak labor, vitamins are used. Medicines, the active component of which is glucose, help to increase the energy potential. Antispasmodic and analgesic drugs are also used. If the occurrence of weak activity could not be avoided, the generic process is enhanced by medication.

Conclusion

The course of labor depends on the degree of the narrow pelvis during pregnancy. In the presence of this problem, the child takes the wrong position, and while moving along the birth canal, he encounters obstacles. In this situation, the fetus extracts surgically... Predicting and preventing the development of a narrow pelvis is quite problematic. The only recommendation that can be given to women faced with such a deviation is to regularly visit the attending physician and undergo all examinations. Also, don't panic. A well-chosen tactic of childbirth will help preserve the health of the woman and the baby.

Features of the size of the pelvis and childbirth are presented in the video:

In obstetrics, there are two concepts of a narrow pelvis: an anatomically narrow pelvis and a clinically narrow pelvis.

The pelvis is considered to be narrow, the skeleton of which is so altered that it creates mechanical obstacles for the passage of a full-term fetus, especially its head. Anatomically narrow is considered a pelvis, one or several sizes of which are reduced by 2 cm or more in comparison with the norm accepted in obstetrics; it is formed during the development of the female body. In some cases, narrowing may be accompanied by deformation of the pelvic bones, in others not. Clinically or functionally narrow is a pelvis that makes it difficult to give birth to a fetus (head) in a given birth.

Anatomical narrowing of the pelvis does not always prevent the birth of the fetus, while the discrepancy between the size of the pelvis and the head of the fetus can be observed with a normal size of the pelvis.

The reasons for the development of an anatomically narrow pelvis are varied. One of them is heredity. In the antenatal period, damaging factors are important, in childhood- poor nutrition, tuberculosis, rickets. During puberty, the leading role in the development of the bone pelvis belongs to the sex hormones of the ovaries and adrenal glands. Under the influence of estrogens, an increase in the transverse dimensions of the pelvis and bone maturation occur, and androgens determine bone growth in length and accelerate the fusion of the epiphyses of the bones. In patients with excessive production of androgens, the following forms of the entrance to the pelvis can be distinguished: longitudinal-oval, round, transverse-oval with normal or increased straight dimensions of the pelvis. Characteristic feature of these forms of the pelvis is a narrow pubic arch.

At present, one cannot but take into account the importance of acceleration in the formation of the transversely narrowed pelvis: due to the rapid growth of the body in length, the increase in transverse dimensions is not fast enough. Most authors note that the shape of the pelvis is a sensitive indicator of the dynamics of sexual development. There is a relationship between the onset of puberty and the corresponding shape of the pelvis in a woman.

The formation of the bone pelvis can be significantly influenced by professional sports. Excessively intense prolonged physical exertion on certain muscle groups during the development of a girl's body during systematic engagement in the same sport leads to a change in the normal proportions of the body. The frequency of anatomically narrow pelvis among athletes is 64.1%, it is highest among gymnasts (78.3%), skiers (71.4%), swimmers (44.4%).

Pelvic deformity in adults can occur as a result of bone neoplasms, osteomalacia, and trauma.

Many classifications of the narrow pelvis have been proposed. Most authors consider it expedient to use the classification of A.Ya. Krassovsky, based on an assessment of the shape of the entrance to the pelvis and the degree of narrowing of the pelvis, depending on the value of the true conjugate.

Classification of the anatomically narrow pelvis (by the shape of the narrowing)

A. Common forms of the pelvis.

1. Generally uniformly narrowed pelvis.

2. The transversely narrowed pelvis.

3. Flat: simple flat pelvis, flat rachitic pelvis, pelvis with a decrease in the wide part of the cavity.

B. Rare forms of the pelvis.

1. Oblique (asymmetric).

2. Pelvis, narrowed by exostoses, tumors.

3. Generally narrowed flat pelvis.

4. Other forms of a narrow pelvis.

The frequency of the anatomically narrow pelvis varies widely (from 2.6 to 15-20%), and in the last decade it has remained quite stable: 3.6-4.7%.

The prevalence rate has changed significantly different forms narrow pelvis. The most common form is uniformly narrowed (40-50%). Less common is a flat pelvis -

0 degree of narrowing of the pelvis is usually judged by the magnitude of the true conjugate.

Classification of the anatomically narrow pelvis (by the degree of narrowing)

1st degree - c.vera not less than 9 cm. II degree - c.vera from 9 to 7 cm.

III degree - c.vera from 7 to 5 cm.

IV degree - c.vera 5 cm or less. With a transversely narrowed pelvis:

I degree - the transverse size of the entrance is 12.4-11.5 cm;

II degree - the transverse size of the entrance is 11.5-10.5 cm;

III degree - the transverse size of the entrance is less than 10.5 cm.The narrowing of the I degree is observed in 90-91%, in the II degree - in 8-9%,

III degree - in 0.2-0.3%.

V modern conditions there are no sharp degrees of narrowing of the pelvis, but more and more often erased forms are found, there is a combination of small degrees of narrowing of the pelvis and large fruits, as well as unfavorable presentations and insertions of the fetal head. V last years obstetricians pay attention to a significant change in the structure of various anatomical forms of the narrow pelvis.

Depending on the shape of the entrance, the X-ray classification includes four types of the pelvis (Fig. 71).

Rice. 71. Caldwell and Moloy classification

Gynecoid type(55% of all pelvis) corresponds to a normal female pelvis. It is a short, wide and capacious basin. The pubic arch is wide, the slope is medium, the curvature of the sacrum is pronounced. The physique is female, the neck and waist are thin, the hips are wide, the mass and height are medium.

Android type(20% of all pelvis) - male pelvis. There is a wedge-shaped entrance, a narrow pubic angle, the sacrum is not bent enough, is deflected anteriorly. The pelvis narrows in a funnel shape downward. The male body type of a woman is noted: broad shoulders, thick neck, waist is not expressed. With this shape of the pelvis, there is the largest number pathology.

Anthropoid type(20-22% of all pelvis) resembles the pelvis of great apes. The shape of the cavity is elongated-oval, the sacrum is narrow and long, the pubic arch is narrow. Features of the physique of such women: tall, lean, wide shoulders, narrow waist and hips, legs long, thin.

Platipelloid type resembles a simple flat basin (3% of all basins). The shape of the entrance to the pelvis is transverse-oval, the slope of the sacrum is medium, the pubic arch is wide. This type is found in tall, thin women with underdeveloped muscles, reduced skin turgor.

In foreign manuals, two classifications of anatomically narrow pelvis are given. One of them is based on an assessment of the shape and degree of narrowing, the other - on the structural features of the pelvis - gynecoid, android, anthropoid, platipelloid.

diagnosis of anatomically narrow pelvis

Timely recognition of a narrow pelvis allows you to prevent a number of complications that arise during pregnancy and childbirth.

For the diagnosis of a narrow pelvis great importance have anamnesis data, primarily about infectious diseases, contributing to a delay in the development of the girl's body, the onset of infantilism and the formation of a narrow pelvis. It is necessary to find out whether the pregnant woman suffered rickets in childhood, tuberculosis of the pelvic bones and joints, trauma to the pelvic bones and lower extremities, followed by lameness.

Information about previous childbirth (duration of labor, weakness of labor, surgical interventions) is of great importance.

health, fetal and maternal injuries, body weight of newborns, the state of health of children in the future).

In the diagnosis of a narrow pelvis, an important place is given to objective research methods. On examination, the general physical development of the pregnant woman is assessed, her height and body weight, changes in the skeleton are determined. Pay attention to the shape of the abdomen: with a narrow pelvis, it has a pointed shape in primiparous and becomes saggy in multiparous.

The main method for diagnosing a narrow pelvis in practical obstetrics is an external obstetric examination, which includes pelvic measurement, which allows you to determine the shape of the pelvis. Along with the traditional measurement of the size of the pelvis, sometimes the sizes of the lateral conjugates (normally 14-15 cm), oblique conjugates (normally 22.5 cm) are determined. Measure the size of the pelvic outlet. An important role in the assessment of the pelvis is played by the measurement of the sacral rhombus (normally 10-11 cm).

The true conjugate is calculated:

Diagonal conjugate;

External conjugate;

By the vertical size of the Michaelis rhombus;

By Frank's size;

Using roentgenopelviometry;

According to ultrasound data.

The capacity of the small pelvis depends on the thickness of its bones, which is indirectly determined by measuring the circumference of the wrist joint with the calculation of the Soloviev index.

Generally uniformly narrowed pelvis. It differs from normal by uniform narrowing of all sizes, for example: 23-26-29-18 cm, a sacral rhombus of the correct shape with sides of 9 cm. Solovyov's index - 13 cm. The pelvis has typical features of a female pelvis with reduced dimensions. I.F. Jordania distinguishes several types of such a pelvis: hypoplastic, children's, male and dwarf pelvis.

Hypoplastic pelvis differs from the normal only in its diminutiveness with the preserved outlines and relationships of the bones inherent in the normal pelvis. This shape of the pelvis is characteristic of stunted peoples.

Children's (infantile) pelvis resembles in shape and structure the pelvis of young girls. The wings of the ilium are more vertical, the pubis

The naya arch is narrow, the sacrum is curved and located vertically far posteriorly between the ilia. The cape is high and protrudes little under the sacral depression. For this reason, the entrance to the pelvis is not transverse-oval, but round or even longitudinal-oval. In women, other signs of infantilism are usually found: short stature, insufficient development of the external genital organs, mammary glands, pubic hair, in the armpits, etc.

Male pelvis. Occurs in tall women strong constitution with massive skeletal bones. The wings of the ilium are steep, the pubic arch is narrow, and the promontory is very high. The pelvic cavity is funnel-shaped.

The basin of the dwarfs. It is characterized by a lag in bone development. The pelvis is usually in proportion to the body.

Transversely narrowed pelvis characterized by a decrease in the transverse dimensions of the small pelvis with normal or increased straight dimensions. The sacrum is often flattened. It is difficult to identify such a pelvis using conventional methods. However, it has a number of anatomical features: steep standing of the wings of the ilium, narrow pubic arch, convergence of the ischial spines, high position of the promontory, a decrease in the transverse size of the pelvic outlet and the transverse size of the sacral rhombus. A classification of the transversely narrowed pelvis is proposed, based on the size of the transverse size of the entrance to the small pelvis (according to roentgenopelviometry data): I degree of narrowing - 12.4-11.5 cm; P - 11.4-10.5 cm; III - less than 10.5 cm.

Simple flat basin characterized by a wide pubic arch; deeper insertion of the sacrum; into the pelvis without changing the shape and curvature of the sacrum; all straight dimensions of both inlet, cavity and outlet are moderately shortened; pelvis size: 25-28-31-18 (17) cm.

The following variants of the pelvis were identified.

1.With an increase in all straight sizes (55%).

2.With a decrease in the straight diameter of the wide part of the pelvic cavity

3.With an increase in only the direct input size (16.5%). This form most often causes a clinically narrow pelvis.

Flat rachitic pelvis is a consequence of the transferred rickets. At the same time, the amount of lime in the bones decreases, the cartilaginous layers thicken. The pressure of the spine on the pelvis and the tension of the musculo-ligamentous apparatus lead to deformation of the pelvis:

measures of the entrance to the pelvis is sharply shortened as a result of deep insertion of the sacrum into the pelvis, the cape protrudes into the pelvic cavity much sharper than normal. The sacrum is flattened and turned anteriorly with its base and posteriorly with its apex. The coccyx is bent anteriorly coracoidly. The shape of the ilium has also changed: their wings are poorly developed, the ridges are deployed, as a result of which the distances Spinarum and Cristarum almost equal. The pubic arch is wide, low. The straight size of the entrance is increased, the transverse size is normal. The pelvis is widened, shortened, flattened, thinned. Its dimensions are 26-27-31-17 cm. The sacral rhombus - with a reduced vertical size, may resemble a triangle.

Generally narrowed flat pelvis is a combination of a generally uniform and flat pelvis, is rare. Sizes 23-26-29-16 cm.

It is also important to determine the position and presentation of the fetus. With a narrow pelvis, oblique, transverse position of the fetus, breech presentation are more common. The presenting head of the fetus before delivery often remains mobile above the entrance to the pelvis.

One of the main methods for assessing the shape and size of the pelvis is vaginal examination, in which the capacity of the pelvis is determined, they try to measure the diagonal conjugate and calculate the true one, i.e. determine the degree of narrowing.

The most reliable information about the shape and size of the pelvis can be obtained using roentgenopelviometry. It is recommended to produce it at 38-40 weeks of pregnancy or before the onset of labor. This method allows you to determine all diameters of the small pelvis, the shape, inclination of the walls of the pelvis, the shape of the pubic arch, the degree of curvature and inclination of the sacrum.

In the last two decades, ultrasound has become widespread. The use of ultrasound scanning for the diagnosis of an anatomically narrow pelvis is reduced to obtaining the size of the true conjugate and the biparietal size of the fetal head.

during pregnancy

The adverse effect of a narrowed pelvis on the course of pregnancy affects only in the last months. In primiparas due to

spatial inconsistencies between the pelvis and the head, the latter does not enter the pelvis and remains mobile above the entrance throughout pregnancy and even at the beginning of labor. The high standing of the head entails a number of other complications. High standing of the diaphragm and limitation of lung excursion contribute to the appearance of shortness of breath earlier than normal. One of the frequent and serious complications of pregnancy with a narrow pelvis is premature (prenatal) effusion, which contributes to the possible development of infection in the uterus and fetal hypoxia.

Complications during pregnancy:

Premature outpouring of water;

Malposition;

Fetal hypoxia;

Loss of small parts of the fetus.

MANAGEMENT OF PREGNANT WOMEN WITH A NARROW PELVIS

Pregnant women with a narrow pelvis should be registered in the antenatal clinic, 1-2 weeks before the expected date of birth, they should be hospitalized in the department of pathology of pregnant women to clarify the weight of the fetus, the size of the pelvis. A labor management plan is developed, and possible delivery routes are specified. Prolonged pregnancy is highly undesirable. In the presence of a narrow pelvis in a pregnant woman and other complications (age, prolonged pregnancy, breech presentation of the fetus, etc.), delivery can be performed by a planned cesarean section.

Features of the course of childbirth:

Early outpouring of water;

Loss of small parts of the fetus;

Clinically narrow pelvis;

Injury to the mother (urogenital fistulas, rupture of the uterus) and fetus, bleeding in the III and early postpartum period.

COURSE AND COMPLICATIONS OF THE I PERIOD OF LABOR

In the first stage of labor, the main complication is the weakness of labor (in 10-37.7% of cases). The second rather frequent complication

nenia - early outpouring of water, which can lead to loss of the umbilical cord, small parts of the fetus. With a protracted course of labor with a long anhydrous interval, the risk of developing endometritis, chorioamnionitis, and ascending infection of the fetus increases significantly.

MANAGEMENT OF THE I PERIOD OF BIRTH

Nowadays, it is generally accepted active expectant tactics of labor management. During labor, cardiac monitoring is desirable. The tactics of labor management with a narrow pelvis is determined individually, taking into account all the data objective research, the degree of narrowing of the pelvis and the prognosis for the woman in labor and the fetus. Childbirth through the vaginal birth canal can proceed: normal; with difficulties, but end well with the right help; with complications that are life-threatening to the mother and fetus. With I and II degrees of narrowing of the pelvis, the outcome of labor depends on the size of the head, its ability to configure, presentation and insertion, the intensity of labor. It should be noted that with the I degree of narrowing of the pelvis, delivery by a full-term fetus is possible provided that there is an average size of the fetus, a good configuration of the head, good labor and compliance of the mechanism of labor with the shape of the narrowing of the pelvis.

With the II degree of narrowing of the pelvis, giving birth to a full-term fetus in some cases is possible, however, with a high risk to the life of the fetus and the health of the mother. Mainly the feasibility of vaginal delivery depends on the size of the fetal head, i.e. clinical compliance.

With III degree of narrowing of the pelvis, giving birth to a full-term fetus through the natural birth canal is possible only after a fruit-destroying operation. With a living fetus, only a cesarean section is indicated.

IV degree of narrowing - absolutely narrow pelvis. Vaginal childbirth is impossible even after a fruit-destroying operation. Cesarean section is the only method of delivery. Currently, III and IV degrees of narrowing are extremely rare.

The fetus in childbirth with a narrow pelvis often suffers from intrauterine hypoxia, which is observed about three times more often than with a normal pelvis.

The main cause of death in children is intrauterine hypoxia and intracranial trauma. With prolonged standing of the fetal head in one plane, almost all fetuses have cardiac activity disturbed.

Currently, perinatal mortality with a narrow pelvis is decreasing, which is associated with an increase in the frequency of caesarean section, with an improvement in intensive care of newborns.

According to which option the childbirth will take place, it is often possible to decide only in the course of the childbirth itself, i.e. when carrying out a functional assessment of the pelvis. Therefore, childbirth is carried out expectantly until signs of a clinically narrow pelvis are revealed. The degree of inconsistency between the head and pelvis of the mother is judged by the following criterion: the absence of translational movement of the fetus along the birth canal (insertion of the head into the pelvis) with good labor. The discrepancy between the fetal head and the mother's pelvis can be detected using the Vasten method (V.A. Vasten is a Russian scientist).

Vasten's sign is positive: when the obstetrician's palm moves from the plane of the bosom to the head, it is noted that there is a "overhanging" of the head, i.e. the plane of the head is above the bosom. The head does not fit the mother's pelvis.

Vasten's sign is weakly positive (level): the plane of the bosom and the head are at the same level - there is a slight discrepancy.

Vasten's sign is negative: the plane of the head is lower than the bosom, - the head corresponds to the mother's pelvis.

REASONS OF NON-CONFORMITY

HEADS OF THE FRUIT AND PELVIS OF THE MAID

1. A small degree of narrowing of the pelvis and a large fetus (60%).

2. Incorrect head insertion - high upright position of the sagittal suture, antero-head or frontal insertion (23%).

3. Large size of the fetus at normal sizes pelvis (10%).

4. Rare anatomical changes in the pelvis - post-traumatic changes, tumors (7%).

5. Insufficient configuration of the head in post-term pregnancy.

Various forms of a narrow pelvis, its anatomical changes determine the corresponding features of the biomechanism of childbirth.

The biomechanism of labor with a generally uniformly narrowed pelvis has the following features.

1. The 1st moment of the biomechanism of childbirth - the flexion of the head occurs in the plane of the entrance to the pelvis, because it is already the first obstacle for the head. The small fontanel becomes lower than the large one.

2. 2nd moment - maximum flexion occurs when moving from a wide part of the pelvic cavity to a narrow one (where flexion normally takes place). A vaginal examination reveals: the small fontanelle is located along the wired axis of the pelvis, being the leading point in childbirth.

3. As a measure of adaptation of the head to the narrowed pelvis during labor, a sharp configuration of the head occurs - a dolichocephalic head (cucumber-shaped) is formed.

4. The 3rd moment of the biomechanism of childbirth - the internal rotation of the head begins in the plane of the narrow part and ends at the exit of the pelvis with the insertion of the head; in this case, the sagittal suture turns into a straight size, and a fixation point is formed - the subooccipital fossa. With a narrow pubic arch, the head is fixed under the pubic arches by two points.

5. 4th moment - extension of the head occurs at the exit of the pelvis by eruption and birth of the head.

6. 5th moment - the inner turn of the shoulders occurs as usual.

Features of biomechanism with a transversely narrowed pelvis

Asynclitic insertion of the head into one of the oblique dimensions of the plane of the pelvic entrance, and with increased straight dimensions of the pelvis, the head is inserted with a sagittal suture into the straight size of the entrance to the pelvis, which is called a high upright position of the sagittal suture.

At transversely in the pelvis, the mechanism of labor may not differ from normal. With mild degrees of discrepancy, the most characteristic mechanism of childbirth is oblique asynclitic insertion of the head (see above). When the transverse narrowing of the pelvis is combined with an increase in the true conjugate, a high upright standing of the head is often formed, which is a measure of the adaptation of the head to the pelvis. If there is a correspondence between the head and the pelvis, the biomechanism of labor consists of the following points: 1) flexion of the head at the entrance to the pelvis; 2) extension of the head at the exit of the pelvis, i.e. no internal

Gates; 3) internal turn of the shoulders, the birth of the fetus. If the head does not match, a clinically narrow pelvis is determined, a cesarean section is performed.

BIOMECHANISM OF LABOR WITH A FLAT PELVIS

Features of the biomechanism of childbirth with a simple flat pelvis

Prolonged standing of the head with a sagittal suture in the transverse size of the entrance of the small pelvis in a state of moderate extension, the sagittal suture can be located asynclitically. Anteroparietal asynclitism is more often observed.

In the cavity of the small pelvis, due to the reduced straight dimensions of its planes, rotation of the head does not occur and the so-called low transverse position of the sagittal suture may occur.

By the beginning of labor, the head is usually movable above the entrance to the pelvis. Insertion of the head with a sagittal suture into the transverse (most favorable) size of the pelvis is the 1st feature of childbirth. 2nd - prolonged standing of the head at the entrance to the pelvis (especially with a rickety pelvis). The 1st moment of the biomechanism is the extension of the head, the leading point is the large fontanelle. Formation of asynclitic head insertion is the 3rd feature. Anterior asynclitism is usually observed, in which the anterior parietal bone descends below the posterior one, located on the protruding promontory. The sagittal suture is located closer to the cape, remaining so until a pronounced head configuration appears. After that, the posterior parietal bone slides off the promontory, the head bends. In the future, the biomechanism proceeds normally. Here, asynclitism is observed, in which the posterior parietal bone descends below the anterior one, and the anterior one, leaning on the pubic articulation, contributes to a more pronounced and longer configuration of the head, which often leads to birth trauma of the woman in labor and the fetus. If the head passes into the plane of entry into the pelvis, then with a simple flat pelvis, it often remains in a state of extension, and childbirth proceeds according to the type of labor in the antero-cephalic presentation: internal rotation into the posterior view, the formation of the 1st fixation point (glabella), flexion of the head and formation of the 2nd point (suboccipital fossa), extension of the head and its birth, internal rotation of the shoulder and birth of the fetus.

Features of the biomechanism of childbirth with a flat rachitic pelvis are reflected in table. eighteen.

Table 18

Features of the biomechanism of childbirth with a flat rachitic pelvis

Variants of head insertion with a flat rachitic pelvis.

1. Synclitic head insertion.

2. Asynclical head insertion.

A. Anteroparietal (non-Gel) asynclitism - the sagittal suture is located closer to the promontory, the anteroparietal bone is inserted (Fig. 72).

B. Posterior parietal (Litsman's) asynclitism - the sagittal suture is located closer to the symphysis (Fig. 73).

With a flat rachitic pelvis, after entering the pelvis, "assault", rapid labor can be observed. And the biomechanism can follow the type of childbirth in the anterior head or in the occipital presentation, i.e. the head in the plane of the narrow part will perform flexion, rotation, in the exit - extension, etc. Due to the long standing of the head and the presence of obstacles, a sharp configuration of the head occurs with the formation of a generic tumor in the region of the large fontanelle (brachycephalic, or tower, head), and with asynclitism, on one of the parietal bones.

Rice. 72. Anteroparietal asynclitism

Rice. 73. Posterior parietal asynclitism

The biomechanism of childbirth with a generally narrowed flat pelvis depends on what prevails: flattening or narrowing. The biomechanism of labor is often mixed, and the course is usually difficult.

FLOWING AND MAINTAINING THE EXPULSION PERIOD

The greatest dangers in childbirth with a narrow pelvis threaten the woman in labor and the fetus in the II stage of labor, when the clinical discrepancy between the pelvis and the head of the fetus is finally revealed.

The main complications of the period of exile should be considered:

Weakness of labor (secondary);

Rupture of the uterus in the lower segment during its overstretching against the background of inconsistency of the head and pelvis and severe labor;

Possible with prolonged standing of the head in one plane of the pelvis, infringement of soft tissues with the subsequent formation of urogenital and intestinal fistulas;

Injuries to the joints and nerves of the pelvis.

In stage II of labor, a functional assessment of the pelvis should be performed. With prolonged childbirth, a large birth tumor appears on the baby's head, and a cephalohematoma may also appear.

clinically narrow pelvis

A clinically narrow pelvis is a concept associated with the process of childbirth. A clinically narrow pelvis should include all cases of discrepancy between the fetal head and the mother’s pelvis, regardless of its size. If in recent years there has been a decrease in the incidence of anatomically narrow pelvis, especially pronounced degrees of narrowing, then the incidence of clinically narrow pelvis is quite stable and amounts to 1.3-1.7% of cases. This is due to an increase in the number of deliveries with large fetuses.

The reasons for the discrepancy between the pelvis of the woman in labor and the head of the fetus can be different: a small degree of narrowing of the pelvis and a large fetus (60%); unfavorable presentation and insertion of the fetal head with small degrees of narrowing and normal size of the pelvis (23.7%); large size of the fetus with normal size of the pelvis (10%); abrupt anatomical changes in the pelvis (6.1%) and other reasons (0.9%); and in post-term pregnancy - insufficient head configuration.

Diagnostic signs of a clinically narrow pelvis:

Prolonged standing of the fetal head in one plane and lack of progress in the II stage of labor;

Pronounced head configuration and birth swelling;

Swelling of the cervix, external genitalia, vaginal mucosa;

Overstretching of the lower segment and high standing of the contraction ring;

Positive signs of Vasten, Zangemeister (only in front view!);

Involuntary pushing activity and the appearance of symptoms of a threatening rupture of the uterus.

Signs of a clinically narrow pelvis can be diagnosed with:

Opening of the cervix more than 8 cm;

Absence of the fetal bladder;

An empty bladder;

Normal contractile activity uterus.

Zangemeister's reception. After measuring the external conjugate of the pelvis, the anterior branch of the pelvis is shifted upward to the most protruding

part of the fetal head. If this size is less than the outer conjugate, then the prognosis for childbirth is good; if more, the prognosis is bad; with equal sizes, the prognosis is uncertain (doubtful) and depends on the nature of labor and the ability of the head to configure.

Obstetric tactics in the development of a clinically narrow pelvis - emergency delivery by caesarean section!

Thus, childbirth with a narrow pelvis passes through the natural birth canal in the presence of a correspondence between the head of the fetus and the mother's pelvis.

Indications for elective caesarean section.

1. Constriction of the pelvis III-IV degree.

2. Pelvic constriction of I and II degrees in combination with a large fetus, breech presentation, prolonged pregnancy.

3. Burdened obstetric history: history of stillbirth, infertility.

4. Scar on the uterus.

5. The presence of genitourinary and genitourinary fistulas.

6. Wrong position of the fetus.

For pain relief in labor with a narrow pelvis, inhalation anesthetics are used, and antispasmodics are widely used. During childbirth, the prevention of fetal hypoxia (glucose, sygetin, cocarboxylase, oxygen) is repeatedly carried out. Episiotomy is often required to prevent perineal tears and speed up labor.

At the end of the II stage of labor, bleeding is prevented (intravenous methylergometrine).

If a clinically narrow pelvis occurs during labor, delivery is carried out by caesarean section (with a living fetus).

Surgical delivery is also performed when a narrow pelvis is combined with other obstetric or extragenital pathology, with a burdened obstetric history.

The imposition of obstetric forceps during childbirth with a narrow pelvis or vacuum extraction of the fetus is very undesirable.

In the successive and early postpartum periods, with a narrow pelvis, bleeding often occurs due to impaired placental abruption, uterine hypotonia, which can be caused not only by complications in the I and II stages of labor, but also (in some cases) by common etiological causes of obstetric bleeding and narrow pelvis.

Therefore, at the beginning III period After childbirth, urine should be removed with a catheter, and after the placenta is excreted, an external massage of the uterus is performed and cold (ice) is placed on the stomach (on the uterus).

With a burdened obstetric history and the threat of bleeding, it is recommended to inject oxytocin intravenously with glucose or saline within 2 hours after delivery.

In the late postpartum period, with improper management of childbirth with a narrow pelvis, postpartum infectious diseases, genitourinary and intestinal fistulas, damage to the pelvic joints can occur.

Health improvement and maternity and childhood protection are the key to reducing the number of women with a narrow pelvis.

The often encountered transversely narrowed pelvis is characterized by a decrease in transverse dimensions by 0.5-1 cm with normal or even increased straight dimensions of the small pelvis. The plane of the entrance to the pelvis is not transverse-oval, but rounded or longitudinal-oval. The sacrum is lengthened, flattened, thickened, due to which the capacity decreases and the height (length) of the pelvis increases. Reduced transverse size of the lumbosacral rhombus. The incidence of the transversely narrowed pelvis is 30-35% of all cases of anatomically narrow pelvis.

Features of the biomechanism of childbirth with a transversely constricted pelvis are that the fetal head is installed with a sagittal suture in an oblique or straight size and, without making an internal rotation, sinks to the pelvic floor, while a posterior view is often formed. With a transversely narrowed pelvis in 40% of cases, there is a clinical discrepancy with the fetal head, secondary weakness of labor, excessive compression of the head in the anteroposterior direction, hypoxic-traumatic damage to the central nervous system in a newborn.

A variant of the transversely narrowed pelvis is the pelvis with a reduced straight size of the wide part of the pelvic cavity (18-20%). For this form of a narrow pelvis, an obstacle arises when the head moves through a wide part of the pelvic cavity. This type of pelvis belongs to the "erased", poorly diagnosed forms and is a consequence of a violation of the development of the skeleton at the age of a girl from 12 to 15 years as a result of hyperandrogenic influences and a reduced content of estrogens in the body.

The lack of natural concavity of the sacrum, its flat shape, determine the equalization of the straight dimensions of the wide and narrow planes of the small pelvis. Depending on the degree of reduction of the direct size of the wide part of the pelvic cavity, the frequency of complications increases: low transverse position of the sagittal suture, oblique asynclitic insertion, difficulty in moving the head in the wide part of the pelvic cavity, secondary weakness of labor. Difficulty moving the head during rhodostimulation can lead to excessive compression and damage to the brain in the fetus (cerebrovascular accident, intracranial hemorrhage, subsequently - infantile cerebral palsy).

The peculiarities of the biomechanism of childbirth is the retention of the fetal head in a wide part of the pelvic cavity with a sagittal suture in a transverse or oblique size. Otherwise, the biomechanism of childbirth is not disturbed.

Flat cans

Flat pelvis. V it shortened the straight dimensions at the normal size of the transverse and oblique dimensions. The narrowing is twofold, therefore, a simple flat and flat rachitic pelvis are distinguished.

Simple flat basin characterized by a decrease in all straight dimensions. The entire sacrum is close to the pubic symphysis. The transverse dimensions of the pelvis are normal or enlarged. The shape of the entrance to the small pelvis is transverse-oval. A characteristic feature of a simple flat pelvis is a decrease in the size of the diagonal and external conjugates. Transverse and oblique dimensions of normal size. There was no deformity of the pelvic or skeletal bones.

Women with a simple flat pelvis have a normal physique. The approximate dimensions of a simple flat pelvis: D. spinarum - 26 cm, D. cristarum - 29 cm, D. trochanterica - 30 cm, C. externa - 18 cm, C. diagonalis - 11 cm, C. vera - 9 cm.

A feature of the biomechanism of childbirth with a flat pelvis is: prolonged standing of the head with a sagittal suture in the transverse dimension at the entrance to the small pelvis and some extension of the head, as a result of which the narrowest part of the entrance is the smallest size (small transverse, equal to 8 cm). If the pelvis is slightly narrowed, the head gradually overcomes the obstacle from the side of the entrance to the pelvis and is born as an occipital presentation. With a significant narrowing of the pelvis, extension of the head alone is not enough. The so-called lateral head declination occurs - asynclitic insertion. Through the narrowed straight size of the entrance, the head does not pass immediately, but, as it were, in parts, first one half, then the other. The adaptive mechanism is the anteroparietal asynclitic insertion, when the anterior parietal bone enters the entrance to the small pelvis first, while the sagittal suture deviates towards the promontory. It should be emphasized that the posterior parietal asynclitic insertion is always a pathology and indicates a complete imbalance between the fetal head and the mother's pelvis.

For flat rachitic pelvis characterized by a decrease in the direct size of the entrance (true conjugate) and an increase in the remaining direct dimensions of the small pelvis. This is due to the displacement of the sacrum around the horizontal axis in such a way that its base approaches the pubic symphysis, and the body and apex, together with the coccyx, are deflected posteriorly. The promontory of the sacrum protrudes sharply forward, in connection with which the entrance to the small pelvis takes the form of a "card" heart. The sacrum is widened, shortened and flattened.

An external examination of the mother's pelvis reveals a number of characteristic features: the wings of the iliac bones are strongly deployed, the distance between the upper anterior iliac spines (D. spinarum) is almost completely close to the size between the iliac crests (D. cristarum). The external conjugate is significantly reduced (up to 17.5-18 cm). The shape of the sacro-lumbar rhombus changes: the vertical diagonal is shortened by 2-3 cm, the upper triangle of the sacro-lumbar rhombus is flattened. At vaginal examination, an additional cape is sometimes revealed, formed as a result of ossification of the cartilage between the vertebrae S I and S II. An accessory cape can impede the advancement of the fetal head. The dimensions of the pelvic outlet are increased (due to the posterior deviation of the apex of the sacrum and the large distance between the ischial tubercles).

Thus, the flat rachitic pelvis is characterized by:

1) reduction of the main size - true conjugates;

2) deformation of the pelvic bones (sacrum);

3) changes in the shape of the entrance to the pelvis;

4) the relative increase in the output of the pelvis. Other signs of previous rickets are also revealed: "square head", S-shaped collarbones, distinct thickenings on the ribs, curvature of the legs, spine, sternum ("chicken breast"), etc.

It should be noted that the pronounced forms of the flat rachitic pelvis are now rare. The main obstacle in childbirth is observed when the head passes through the plane of the entrance to the small pelvis.

The biomechanism of childbirth: the fetal head stands for a long time over the entrance to the small pelvis with a sagittal suture in the transverse size, there is some extension of the head and its asynclitic (anteroparietal) insertion. When the head passes the plane of the entrance to the small pelvis, narrowed in a straight size, then it advances rapidly, since all other direct dimensions of the small pelvis are enlarged due to the deviation of the sacrum and coccyx posteriorly. The rapid advancement of the head through the shortened pelvis is accompanied by a high threat of the development of a birth injury in the fetus, significant ruptures of the birth canal.

Distinguish between anatomically narrow pelvis (3-7%) and clinically narrow pelvis (3-5%). Diagnosis of anatomically narrow pelvis is carried out before or during pregnancy and after childbirth, clinically narrow pelvis - only during childbirth.

Anatomically narrow pelvis- this is a narrowing of 1 or more external dimensions of the pelvis by 1.5-2 cm or more.

Clinically narrow pelvis- this is a discrepancy between the size of the fetus and the size of the woman's pelvis.

Classification:

By form:

a) common: a transversely narrowed pelvis (1 place due to acceleration, emancipation, the appearance of roentgenopelviometry); flat pelvis: - a pelvis with a reduced straight size of the plane of the wide part of the pelvic cavity; - a simple flat basin; - flat rachitic pelvis; general uniformly narrowed pelvis.

b) rare: oblique pelvis; pelvis narrowed by various tumors.

By the degree of narrowing: Litzman classification (based on the size - conjugata verae, which is normal = 11cm). 1 degree of narrowing - 11-9 cm; 2 degree - 9 - 7 cm; 3 degree - 7 - 5 cm; 4 degree - less than 5 cm.

Methods for measuring true conjugates:

External conjugate (NK): NK - 9 cm. Normally NK = 20 cm. For the diagonal conjugate: 13 cm - 2 cm = 11 cm. For the vertical size of the Michaelis rhombus (Litzmann's size), which is equal to the true conjugate. X-ray genopelviometry (performed before the expected pregnancy). Ultrasound examination, NMR.

Sizes of a normal pelvis:

Small pelvis:

Entrance plane: pr p (conjugata verae) - 11, pri p - 13.5, braid p - 12cm

Wide part: pr p - 12.5, pop p - 12.5, braid p - 13

Narrow part: pr p - 11, pop p - 10.5

Output: pr p - 9.5 to 11.5 stretch, pop p - 11.

Outdoor distances: spinarum - 25-26, kristarum - 28-29, trochanterica - 30-31, nar conjuga - 20cm

The transversely narrowed pelvis

Pelvic measurement is not very informative. Diagnostics is carried out using roentgenopelviometry. The basis classification according to the degree of narrowing, the size of the plane of the entrance to the small pelvis is set: 1 degree of narrowing - 11.5-12.5 cm. 2 degree of narrowing - 11.5-10.5 cm. 3 degree of narrowing - less than 10.5 cm.

Diagnostics: Small spread of the iliac wings. Acute pubic angle. Rapprochement of the sciatic spines. Easy reachability of the terminal line. The size of Tridandania (the transverse size of the Michaelis rhombus) is reduced (normally 10 cm). The transverse size of the exit (between the ischial tubercles) is less than 11 cm (normally 11 cm). Male body type.

Childbirth at 1 and 2 tbsp is possible through the natural birth canal with a favorable mechanism of childbirth. 3st - indication for COP.

Features of the biomechanism of childbirth: High upright standing of the head (in front view - swept seam in straight size). Oblique anterior asynclitism (anterior parietal bone in oblique size and in a state of slight flexion).

Pelvis with reduced straight size of the plane of the wide part of the pelvic cavity

Typically: Flattening of the sacrum up to the absence of curvature. Elongation of the sacrum. No difference between the straight dimensions of all planes. Reduction of the pubic-sacral size (the distance from the middle of the symphysis to the articulation between the 2 and 3 sacral vertebrae; normal = 22 cm).

Features of the biomechanism of childbirth: Insertion and advancement of the head with a swept seam in a transverse dimension. Internal rotation of the head with the back of the head anteriorly occurs during the transition from the wide part to the narrow one.

The course of pregnancy: high standing of the diaphragm is characteristic, limitation of lung excursion, shortness of breath, abnormal position of the fetus, premature rupture of amniotic fluid, since the head does not descend for a long time, a pointed pendulous abdomen is characteristic.

Pregnancy management: Anamnesis. Obstetric history. Ultrasound (but no more than 5 times because the bones of the fetal skull become denser, fontanelles decrease and the configuration of the head may be absent). Antenatal hospitalization for the prevention of premature rupture of amniotic fluid, the prevention of anomalies, and the determination of the body's readiness for childbirth. Prevention of a large fetus (now 10% of pregnant women have a large fetus). Conduct anatomical assessment of the pelvis.

Labor management: With a narrow pelvis, all complications of childbirth occur, forceps are not applied. Tactics depend on the degree of narrowing: 1 and 2 st - a relative indication for the COP; 3 tbsp - with a living fetus - KS, with a dead fetus - a fruit-destructive operation is possible. 4 tbsp narrowing - absolute reading to the COP.

Possible complications during childbirth: Prolonged standing of the head in one plane (no advancement of the head for 1 hour), which leads to compression of soft tissues between the bones of the fetal skull and the bones of the pelvis and the formation of genital fistulas. Incorrect head insertion. High maternal trauma: perineal rupture, perineo- and episiotomy, rupture of the uterus, pubic and sacroiliac joints. High fetal trauma: intracranial hemorrhages (as a result of increased intracranial pressure), cephalohematomas (subperiosteal hemorrhages),  stillbirth. Premature attempts (the head is still in the plane of the entrance to the small pelvis. Clinically narrow pelvis.

Prevention of complications during childbirth with a narrow pelvis: Take into account the peculiarities of the biomechanism of childbirth. For a more favorable insertion of the head, it is recommended in the first period to lie on its side, corresponding to the position of the fetus, until the head is inserted and not to walk. Perineo- and episiotomy. Functional assessment of the pelvis during labor.

Signs of a clinically narrow pelvis: Incorrect insertion of the head. Positive sign of Vasten. Positive sign of Tsangemeister (the button of the pelvis is moved from the upper edge of the pubic articulation to the fetal head (presenting part) and if the size increases, then the sign of Tsangemeister is positive, if it decreases - negative. Symptoms of threatening uterine rupture. Long standing of the head in one plane or lack of translational movement of the head with full opening of the cervix, which swells Symptoms of urinary tract clamping (catheterization is impossible, the bladder is full, as a result of trauma to the urethra, there may be hematuria, an increase in body temperature).

When diagnosing a clinically narrow pelvis - deliver by KS on an emergency basis. Enhancement of labor is contraindicated, as there may be a rupture of the uterus.

Update: October 2018

A narrow pelvis is rightfully considered one of the most difficult and complex sections in obstetrics, since this pathology is fraught with the development of various complications in childbirth, especially if they are mismanaged. According to statistics, anatomical narrowing of the pelvis occurs in 1 - 7.7%, and in childbirth, such a pelvis becomes clinically narrow in 30%. The total number of all births accounts for 1.7% of clinically narrow pelvis.

The concept of "narrow pelvis"

In the period of pain, when the fetus is expelled from the uterus, it must overcome the bony ring of the birth canal, that is, the small pelvis. The pelvis consists of 4 bones: 2 pelvic bones, formed by the iliac, pubic and ischial bones, the sacrum and the coccyx. These bones contact each other with the help of cartilage and ligaments. In women, the pelvis, in contrast to men, is wider and more voluminous, but has a shallower depth. Normal parameters of the pelvis play an important role in the physiological, without complications, course of labor. In the presence of deviations in the configuration and symmetry of the pelvis and a decrease in size, the bone pelvis acts as an obstacle to overcoming its fetal head.

In practical terms, a narrow pelvis is divided into 2 types:

• anatomically narrow pelvis, which is characterized by a decrease in one / several sizes by 2 cm or more;
• a clinically narrow pelvis develops when there is a discrepancy in childbirth between the size of the baby's head and the anatomical size of the woman's pelvis (but even in the case of anatomical narrowing of the pelvis during childbirth, a functionally narrow pelvis is not always possible, for example, if the fetus is small, and vice versa, with normal anatomical parameters and a large baby is likely to develop a clinically narrow pelvis).

Causes

The reasons for the formation of a narrow pelvis differ with its anatomical narrowing or the appearance of a disparity in the size of the baby's head and the pelvic size of the mother.

Etiology of anatomically narrowed pelvis

The following factors are capable of provoking the formation of an anatomically narrowed pelvis:

• glitches in menstrual function, impaired fertility, late onset of menstruation;
• neuroendocrine pathology;
• frequent colds and excessive exercise stress in adolescence;
• inadequate nutrition, hard physical work in childhood.

Anatomical narrowing of the pelvis is caused by the following reasons:

• infantilism, both general and sexual;
• lag in sexual development;
• rickets;
• osteomalacia, bone tuberculosis and bone tumors;
• fractures of the pelvic bones;
• curvature of the spine (lordosis and kyphosis, scoliosis and tailbone fractures);
• cerebral palsy;
• features of the constitution and heredity;
• polio;
• exostoses and pelvic tumors;
• damaging factors in the antenatal period;
• acceleration (rapid growth of the body in length and at the same time slowing down the increase in transverse pelvic dimensions);
• stressful situations and psychoemotional stress, which contribute to the emergence of "compensatory hyperfunction of the body", which forms a transversely narrowed pelvis;
• professional sports (gymnastics, skiing, swimming);
• disturbed mineral metabolism;
• hypo- and hyperestrogenism, androgen excess;
• dislocation of the hip joints.

Etiology of the functionally narrow pelvis

The disproportion in childbirth between the baby's head and the mother's pelvis is caused by:

• anatomical narrowing of the pelvis;
• large size and weight of the fruit;
• difficulties in the configuration of the fetal cranial bones (true overmaturity);
• wrong position of the unborn baby;
• pathological head insertion (asynclitism, frontal insertion, etc.);
• neoplasms of the uterus and ovaries;
• narrowing (atresia) of the vagina;
• presentation by the pelvic end (rare).

Childbirth, complicated by a clinically narrow pelvis, in 9 - 50% ends with a cesarean section.

Narrow pelvis: varieties

There are many classifications of anatomically narrowed pelvis. Often in the obstetric literature there is a classification based on morphoentgnological signs:

Gynecoid type

It accounts for 55% of the total number of pelvis and is a normal female type pelvis. The body type of the expectant mother is female, she has a thin neck and waist, and her hips are wide enough, weight, height is within average.

Android pelvis

It occurs in 20% and is a male-type pelvis. A woman has a masculine physique, against the background of wide shoulders and narrow hips, there is a thick neck and an inexpressible waist.

Anthropoid pelvis

It is 22% and is inherent in primates. This shape is distinguished by an increase in the direct size of the entrance and a significant excess of its transverse size. Women with such a pelvis are characterized by high growth and leanness, the shoulders are wide enough, and the waist with the hips is narrow, and the legs are elongated and thin.

Platipeloid pelvis

It is similar in shape to a flat pelvis, observed in 3% of cases. Women with a similar pelvis are tall and thin, underdeveloped muscles and reduced skin elasticity.

Narrowed pelvis: forms

The classification of the narrow pelvis, proposed by Krassovsky:

Forms that are common

• a general uniformly narrowed pelvis (ORST) is the most common type and is observed in 40 - 50% of all cans;
• transversely narrowed pelvis (Robert's);
• flat pelvis, is 37%;
  • simple flat (Deventrovksiy);
  • flat rachitic;
  • a pelvis with a reduced wide part of the pelvic cavity.

Forms that are rare

• oblique and oblique;
• deformation of the pelvis by bone tumors, exostoses and fractures;
• other forms:
  • generally narrowed flat;
  • funnel-shaped;
  • kyphotic form;
  • spondylolisthetic form;
  • osteomalacia;
  • assimilation.

Narrowing degrees

The classification based on the degree of constriction proposed by Palmov:

• By the length of the true conjugate (norm 11 cm) and refers to the ORST and the flat pelvis:
  • 1 tbsp. - less than 11 cm and not shorter than 9 cm;
  • 2 tbsp. - indicators of true conjugates 9 - 7.5 cm;
  • 3 tbsp. - the length of the true conjugate is 7.5 - 6.5 cm;
  • 4 tbsp. - shorter than 6.5 cm, which is called an "absolutely narrow pelvis".
• The size of the transverse diameter of the entrance to the small pelvis (normal size 12.5 - 13 cm) and refers to the transversely narrowed pelvis:
  • 1 tbsp. - transverse diameter of the entrance within 12.4 - 11.5;
  • 2 tbsp. - the value of the transverse diameter of the entrance is 11.4 - 10.5;
  • 3 tbsp. - the transverse diameter is shorter than 10.5.
• By the size of the straight diameter of the wide part of the pelvic cavity (normally 12.5 cm):
  • 1 tbsp. - diameter 12.4 - 11.5;
  • 2 tbsp. - diameter is less than 11.5.

Dimensions of the anatomically narrowed pelvis of different shapes

Narrow basin: dimensions (table, in cm)

Dimensions Pelvis shape
	normal	transversely	ORST	flat rachitic	Simple flat
outdoor	25/26 – 28/29 – 30/31	24 – 26 – 29	24 – 26 – 28	26 – 26 – 31	26 – 29 – 30
External conjugate	20 – 21	20 – 21	18	17	18
Diagonal conjugate	13	13	11	10	11
True conjugate	11	11 – 11,5	9	8	9
Michaelis rhombus:
Vertical diagonal	11	11	Less than 11	Less than 9	Less than 9
Horizontal diagonal	10 — 11	Less than 10	Less than 10	Less than 10	Less than 10
Exit plane:
straight	9,5	9,5	Less than 9.5	9,5	Less than 9.5
transverse side conjugate
Differential criterion	Absent	Shortening transverse dimensions	Uniform reduction of all parameters by 1.5 cm or more	Reduction of the straight size of the plane of the entrance to the pelvis	Reducing the straight dimensions of all planes

Diagnostics

The narrowed pelvis is evaluated and diagnosed in antenatal clinic, on the day the pregnant woman was registered. To identify a narrow pelvis during pregnancy, the doctor examines the history, conducts an objective study, which includes anthropometry, examination of the body, palpation of the pelvic bones and uterus, measurement of the pelvis and vaginal examination. If necessary, special methods are prescribed: roentgenopelviometry and ultrasound scanning.

Anamnesis

It is very important to pay attention to the diseases and living conditions of a pregnant woman in childhood and adolescence (rickets and poliomyelitis, osteomyelitis and bone tuberculosis, hormonal imbalances, poor nutrition and hard physical work, intense sports activities, injuries and chronic pathology). The obstetric history data are essential:

• how was the previous birth;
• why was the operative delivery performed, whether the newborn had traumatic brain injury;
• whether there was a stillbirth or death of a child in the neonatal period.

Objective research

Anthropometry

Low growth (145 cm or less) usually indicates a narrowed pelvis. But a narrowing of the pelvis (transversely) is also possible in tall women.

Evaluated: gait, physique, silhouette

It has been proven that in the case of a strong bulging of the abdomen forward, the center of the upper half of the body is displaced posteriorly in order to maintain balance, and the lower back moves forward, thereby increasing the lumbar lordosis and the angle of inclination of the pelvis.

The shape of the abdomen is assessed

It is known that a primiparous pregnant woman has elastic abdominal wall and the abdomen takes on a pointed shape. In multiparous, the abdomen is saggy, since the head is not inserted into the entrance of the narrow pelvis at the end of the gestation period, and the uterine fundus is high, while the uterus itself deviates from the hypochondrium up and forward.

• Identifying signs of sexual infantilism or virilization.
• Inspection and probing of the Michaelis rhombus

The Michaelis rhombus consists of the following anatomical structures:

• above - the lower border of the 5th lumbar vertebra;
• below - the top of the sacral bone;
• on the sides - the posterior superior protrusions (spines) of the iliac bones.

Palpation of the pelvis

Palpation of the iliac bones reveals their sloping, contours and location. Palpation of the trochanters (large trochanters of the femur) can diagnose an obliquely displaced pelvis in case of their deformation and standing at different levels.

Vaginal examination

It makes it possible to determine the capacity of the pelvis, to examine and evaluate the shape of the sacrum, the depth of the sacral cavity, whether there are bony protrusions, deformation of the lateral pelvic walls, to measure the height of the symphysis and the diagonal conjugate.

Measuring the pelvis

Basic measurements:

• Distantia spinarum is a segment between the anterior superior protrusions of the iliac bones. The norm is 25 - 26 cm.
• Distantia cristarum - the segment between the most distant places of the iliac crests. Norm 28 - 29 cm.
• Distantia trohanterica - the segment between the trochanters of the thigh bones, the norm is 31 - 32 cm.
• External conjugate - the distance is measured that starts from the upper edge of the bosom and ends with the upper corner of the Michaelis rhombus. The norm is not less than 20 cm.
• Measurement of Michaelis rhombus (vertical diagonal 11 cm, horizontal diagonal 10 cm). The asymmetry of the rhombus indicates a curvature of the pelvis or spinal column.
• Soloviev index - the circumference of the wrist is measured at the level of the prominent condyles of the forearm. With the help of this index, the thickness of the bones is assessed: a small index indicates the thinness of the bones, and, therefore, a greater capacity of the pelvis. Norm 14.5 - 15cm.
• Determination of the pubic-sacral size (the segment is measured from the middle of the symphysis to the point where the 2nd and 3rd sacral vertebrae join). Norm 21.8 cm.
• The pubic angle is measured (normally 90 degrees).
• The height of the pubic articulation is determined
• The uterus (coolant and WDM) is measured to find out the estimated weight of the fetus.

Additional measurements:

• measure the angle of inclination of the pelvis;
• measure the output of the pelvis;
• if an asymmetry of the pelvis is suspected, the oblique dimensions and the lateral Kerner conjugate are determined.

Special research methods

Roentgenopelviometry

Carrying out is allowed X-ray examination after 37 weeks and in labor. With its help, the structure of the pelvic walls, the shape of the entrance, the degree of inclination of the pelvic walls, the features of the ischial bones, the severity of the sacral curvature, the shape and size of the pubic arch are determined. Also, this method provides an opportunity to find out all the diameters of the pelvis, bone tumors and fractures, the size of the child's head and its position in relation to the pelvic planes.

Ultrasound

It makes it possible to determine the true conjugate, the location of the head and its size, to evaluate the features of the head insertion. All diameters of the pelvis are determined using a transvaginal probe.

How to calculate the true conjugate

The following methods are used:

• subtract from the size of the external conjugate 9 (normally at least 11 cm);
• 1.5 - 2 cm is subtracted from the value of the diagonal conjugate (for values ​​of the Soloviev index of 14 - 16 cm or less, subtract 1.5, in the case of the Soloviev index of more than 16, subtract 2);
• by Michaelis rhombus: its vertical size corresponds to that of the true conjugate;
• according to the data of roentgenopelviometry;
• according to ultrasound examination pelvis.

How is the pregnancy going?

In the first half of the gestation period, complications with a narrowed pelvis are not observed. The nature of the course of the second half of gestation is affected by the underlying disease, which led to the formation of a narrow pelvis, in addition, extragenital pathology and emerging complications (gestosis, intrauterine infection, etc.) affect. Pregnant girls with a narrow pelvis are characterized by:

• the formation of a pointed abdomen in primiparous and sagging in multiparous, which provokes asynclitic insertion of the head during childbirth;
• the risk of premature birth increases;
• excessive fetal mobility, which contributes to abnormal fetal positions, breech presentation and extensor presentations;
• often pregnancy is complicated by the premature outpouring of water due to the absence of a contact belt with a high standing of the head;
• high standing of the head due to the impossibility of inserting it into the pelvis, which causes high standing of the uterine fundus and diaphragm and leads to increased heart rate, shortness of breath and rapid fatigue.

Pregnancy care

All expectant mothers with a narrow pelvis are registered with an obstetrician-gynecologist. A couple of weeks before giving birth, a woman is hospitalized in the antenatal department in a planned manner, where the gestational age is specified, the estimated weight of the fetus is calculated, the pelvis is re-measured, the position / presentation of the fetus, its condition is clarified, and the choice of the method of delivery is being decided (a management plan is being developed).

The method of delivery is determined on the basis of anamnestic data, the anatomical shape of the narrowing of the pelvis and the degree, estimated weight of the child and other complications of gestation. Physiological childbirth can be carried out in the case of premature pregnancy, 1 degree of narrowing and normal size of the child, mature cervix and in the absence of a burdened obstetric history.

A planned caesarean section is performed if the following indications are present:

• a combination of 1 - 2 degrees of narrowing and a large fetus, breech presentation, fetal position anomaly, post-term pregnancy;
• "Old" primiparous, the presence of a stillbirth in a previous birth or complicated labor and the birth of a fetus with birth trauma;
• a combination of a narrow pelvis and other obstetric pathology, which requires prompt delivery;
• 3-4 degree of a narrowed pelvis (rarely found today).

Pregnancy and pelvic pain

Pain in the pelvic bones occurs after 20 weeks and is due to various reasons:

Lack of calcium

The pain is constant and aching, not associated with movement or change in body position. It is recommended to take calcium supplements in combination with vitamin D.

Sprains of the uterine ligaments and dehiscence of the pelvic bones

The larger the size of the uterus, the stronger the tension of the uterine ligaments that hold it, which is manifested by pain and discomfort when walking and moving the child. This is caused by prolactin and relaxin, under the influence of which the ligaments and pelvic cartilage swell and soften in order to "soften" the passage of the child through the bone ring. A brace should be worn to relieve pain.

Discrepancy of the pubic articulation

Too much swelling of the symphysis (a rare pathology) is accompanied by bursting painful sensations in the pubis, and it is also impossible to raise a straight leg in a horizontal position. This pathology is called symphysitis, which is accompanied by a divergence of the pubic articulation. Effectively surgical treatment, which is carried out after childbirth.

The course of labor

Today, the tactics of childbirth with a narrow pelvis provides for a significant increase in indications for abdominal delivery, both planned and emergency in case of complications. Maintaining the birth process through the natural birth canal is a difficult task, since the outcome can be either favorable or unfavorable for a woman and a child. In cases of 3-4 degrees of narrowing, the birth of a live and full-term fetus is impossible - a planned operation is performed. If the pelvis is narrowed to 1 and 2 degrees, the successful completion of labor depends on the indicators of the baby's head, its ability to configure itself, the nature of the insertion of the head and the intensity of labor.

What are the complications of a narrow pelvis during childbirth?

First period

During the period of opening of the uterine pharynx, childbirth may be complicated:

• weakness of the birth forces (10 - 38%);
• early rupture of amniotic fluid;
• prolapse of the umbilical cord / small parts of the baby;
• oxygen starvation of the fetus.

Second period

During the period of fetal expulsion, the following complications may develop:

• the emergence of secondary weakness of the birth forces;
• intrauterine hypoxia;
• the threat of uterine rupture;
• necrosis of tissues of the birth canal with the formation of fistulas;
• damage to the pubic articulation;
• damage to the pelvic plexus.

Third period

The last period of childbirth, as well as the early postpartum period, are fraught with bleeding, due to a long course of labor and an anhydrous gap.

Labor management

Today, the most reasonable tactic for carrying out childbirth in the described pathology is recognized as active-expectant. Moreover, the tactics of giving birth should be individual and take into account not only the results of an objective study of the woman in labor, the degree of narrowing of the pelvis, but also the prognosis for the woman and the child. The childbirth plan should include the following points:

• bed rest, which prevents early discharge of water (the woman's position should be on the side to which the fetus's back is);
• prevention of weakness of labor forces;
• prevention of intrauterine fetal starvation;
• prevention of infectious complications;
• identification of signs of clinical non-compliance;
• preventive measures of subsequent and early postpartum hemorrhage;
• carrying out a cesarean section (if indicated) with a living fetus;
• fruit-destructive operation in case of fetal death.

During childbirth, discharge from the genital tract (mucous membranes, water leakage or bloody), the condition of the vulva (swelling), and urination are controlled. In case of urinary retention, catheterization is performed Bladder but it should be remembered that given sign may indicate a disproportion between the pelvic sizes of the woman in labor and the baby's head.

The most common complication of childbirth with a narrowed pelvis is premature effusion of water. If an "immature" cervix is ​​detected, then operative delivery is performed. In the case of a "mature" cervix, labor induction is shown (if the estimated weight of the fetus is not more than 3600 grams and there is 1 degree of narrowing).

During the period of contractions, to prevent their weakness, an energy background is created, the woman in labor is provided with medication-induced sleep-rest in a timely manner. In the process of assessing the effectiveness of labor, the doctor must control not only the dynamics of cervical dilatation, but also how the head moves along the birth canal.

Rhodostimulation should be carried out with caution, and its duration should not exceed 3 hours (if there is no effect, a cesarean section is performed). In addition, in the first period, antispasmodics are necessarily introduced (every 4 hours), the Nikolaev triad is performed (prevention of hypoxia) and antibiotics are prescribed with an increasing waterless gap.

The period of expulsion is complicated by the development of secondary weakness, intrauterine hypoxia of the baby, and prolonged standing of the baby's head in the birth canal provokes the formation of fistulas. Therefore, an episiotomy is performed and the bladder is emptied in a timely manner.

Disproportion of the head and pelvis of the woman in labor

The emergence of a clinically narrow pelvis is mainly promoted by:

• a slight degree of narrowing and a large baby;
• unsuccessful head insertions or incorrect presentation of the fetus;
• large fetal head with normal pelvic dimensions;
• abnormal forms of narrowing of the pelvis.

During childbirth, a functional assessment of the pelvis must be performed, which includes:

• determination of the features of the insertion and assessment of the biomechanism of labor when the insertion is detected;
• the head configuration is evaluated;
• diagnosis of a generic tumor on soft tissues heads, the speed of its appearance and growth;
• identification of signs of Vasten and Tsangeimester (assessed after the outpouring of waters).

Signs of a clinically narrow pelvis are as follows:

• the biomechanism of childbirth is disrupted, that is, it does not correspond to this type of pelvic narrowing;
• the head of the fetus does not advance, although the uterine pharynx is fully open, the water has moved away, and the contractions are of sufficient strength;
• the appearance of attempts when the child's head is pressed against the entrance from the pelvis;
• symptoms of pressing of soft tissues and urea (swelling of the cervix and vulva, delayed urination, blood is determined in the urine);
• positive signs of Vasten, Tsangeimester;
• a clinic of the threat of uterine rupture appears;
• protracted course of the first period;
• significant head configuration;
• early or premature outpouring of water.

Vasten's sign is determined by touch (the ratio of the baby's head and the entrance to the pelvis is found out). A negative sign of Vasten is a condition when the head is inserted into the small pelvis, located below the pubic articulation (the doctor's palm has dropped below the bosom). Symptom level - the palm of the obstetrician lies at the level of the bosom (the head and symphysis are in the same plane). A positive sign - the doctor's palm is located above the symphysis (the head is above the bosom). In the case of a negative sign, childbirth ends on its own (the head and the size of the pelvis correspond to each other). With a symptom on a level, spontaneous childbirth is possible, subject to effective labor and an adequate configuration of the head. In the case of a positive sign, independent childbirth is impossible.

Kalganova proposed to distinguish 3 degrees of discrepancy between the pelvic dimensions and the head of the child:

1 tbsp. or relative inconsistency

Correct head insertion and good configuration are noted. Contractions of sufficient strength and duration, but the dilatation of the cervix and the advancement of the head are slowed down, in addition, the water leaves out of time. Difficulty urinating, but Vasten's sign is negative. Self-completion of labor is possible.

2 tbsp. or a significant mismatch

The biomechanism of childbirth and the insertion of the head do not correspond to normal, the head is sharply configured and stands in the same plane for a long time. Anomalies of labor forces (discoordination or weakness), urinary retention are added. Vasten's symptom is level.

3 tbsp. or an absolute mismatch

Attempts appear prematurely against the background of a lack of forward movement of the head, despite good contractions and full opening... The generic tumor is rapidly growing, there are signs of pressing the urea, there is a clinic of the threat of uterine rupture. A positive sign of Vasten is diagnosed.

The second and third degrees of inconsistency serve as an indication for immediate operative delivery.

Practical example

V maternity ward a primiparous 20 years old was delivered with complaints of contractions for 2 hours. There was no outpouring of water. The condition of the woman in labor is satisfactory, pelvic dimensions: 24.5 - 26 - 29 - 20, coolant - 103 cm, the height of the uterine fundus is 39 cm. The fetus is located longitudinally, the head is pressed against the entrance. Auscultatory: the fetal heartbeat is clear, does not suffer. Contractions of good strength and duration. The estimated weight of the child is 4000 gr.

When conducting a vaginal examination, it was revealed: the cervix is ​​smoothed, has thin and extensible edges, the disclosure is 4 cm.Waters are whole, fetal bladder is functioning. The head is pressed against the inlet. The cape is not accessible. Diagnosis: Pregnancy 38 weeks. 1 period 1 first term labor. Large fruit. The transversely narrowed pelvis of the 1st degree.

After 6 hours of active contractions, a second vaginal examination was performed: The cervix was open to 6 cm, there is no fetal bladder. The head is pressed to the entrance by a sagittal suture in a straight size, the small fontanel is anteriorly.

Diagnosis: Pregnancy 38 weeks. 1 period 1 delivery at a time. The transversely narrowed pelvis of the 1st degree. Large fruit. High straight standing sagittal seam.

It was decided to end the labor with surgery (incorrect insertion, narrowing of the pelvis, large fetus). C-section passed without complications, a fetus weighing 4300 grams was removed.