Narrow pelvis during pregnancy: dimensions and classification, possible complications during childbirth. Narrow pelvis and its causes

There are two options - anatomically narrow pelvis, it can be detected during pregnancy, and clinically narrow, which is established only during childbirth. Anatomical signs of a narrow pelvis:

Michaelis rhombus. This is an imaginary figure that is obtained by connecting four anatomical points. If an equilateral rhombus is obtained, this indicates well-developed pelvic bones. Spinal curvature is a reason for examination.
Solovyov index. This is the circumference of a woman's wrist. Normally, the Solovyov index is from 15 to 17 cm, less indicates thin bones, more indicates massive bones, which can complicate childbirth.
Pelvic parameters. There are four sizes for the female pelvis.

Externally, it is sometimes difficult to identify a narrow pelvis, especially grades 1-2. Additional data for analysis: waist-buttock ratio, height, foot size, arms and fingers. On the eve of childbirth, in women with obvious incompatible sizes of the baby and pelvis, the stomach hangs forward.

Anatomy of the female pelvis

Clinical pelvic discrepancy is established only during childbirth after the cervix has fully opened and descent of the fetus should occur. If the size of the fetal head is larger than the internal diameter of the entrance to the cavity pelvic bones, the child cannot be born through the normal birth canal. Before the onset of contractions, it can be assumed in women: with a pregnancy of more than 4 kg; with hydrocephalus in a baby; with an abnormal location of the head in the pelvic cavity; with developmental defects in the fetus.

Reasons for the formation of a narrow pelvis: often bones are formed constitutionally in girls, the likelihood is higher in women who have undergone the following diseases: vitamin D deficiency in childhood; poor nutrition; injuries; bone growths in the area of the pelvic bones, for example, osteomas; hormonal disorders; bone infections; other diseases bone tissue.

The first and second ones are more common degree of narrowing, third and fourth - only for serious diseases of the bone tissue or general underdevelopment of the girl’s skeleton.

The effect of a narrow pelvis on pregnancy none. The only thing that women may notice is that lower back pain is more pronounced due to a sagging belly; movements of the child in atypical places - not in the right hypochondrium, but on the right or left below.

Without timely diagnosis, complications during childbirth are possible: outpouring amniotic fluid before contractions begin; prolapse of the child’s arms, legs and umbilical cord loops due to water leakage; weak or abnormal; labor lasting more than 8-12 hours; injuries to the skull bones and soft tissues of the fetal head, collarbone fractures; serious injuries to a woman's birth canal.

Women with anatomical narrowing of the pelvis are hospitalized in the pregnancy pathology department on the eve of birth - 1-2 weeks before. A decision is made about delivery - through natural ways or planned caesarean section. At clinical narrowing Absence of progress in labor within 2 hours, estimated weight of the child more than 4 kg or a decrease in pelvic size are indications for surgery.

Caesarean section will be mandatory, if: the last and penultimate degrees of narrowing; detection of bone growths in the pelvis; changes in the anatomy of the pelvis due to injuries and diseases; symphysiopathy with rupture in previous births; fetal weight more than 4 kg, part down; the presence of scar changes on the uterus, structural anomalies; with intrauterine fetal suffering according to ultrasound results and with green amniotic fluid Oh.

Read more in our article about all the features of a narrow pelvis and childbirth options.

Read in this article

Signs of an expectant mother

There are two options - an anatomically narrow pelvis, which can be identified during pregnancy, and a clinically narrow one, which is established only during childbirth. The reasons and tactics for treating a woman have similar positions, but there are also fundamental differences.

Anatomical narrowings are established based on the examination of the pregnant woman during registration. Attention is paid to the following signs:

Michaelis Rhombus. This is an imaginary figure that is obtained by connecting four points: at the top - the end of the vertebral line, at the bottom - the top of the intergluteal fold, the side points - the sacral fossae. If an equilateral rhombus is obtained, this indicates well-developed pelvic bones and the absence of deformities.
Scolicosis, as well as other bone abnormalities, lead to the formation of an irregular rhombus, which always alerts the doctor and gives impetus to further examination.

Michaelis rhombus: 1 – normal; 2 – flat; 3- uniform reduction of all sides; 4 – oblique changes.

Solovyov index. This is the circumference of a woman's wrist. The smaller, the more fine-boned it is considered, which means that the pelvic cavity will be voluminous, and the likelihood of narrowing is less. Normally, the Solovyov index is from 15 to 17 cm, less indicates thin bones, more indicates massive bones, which can make it difficult for the baby to pass through the birth canal.
Pelvic parameters. There are four sizes for the female pelvis, based on which it is determined whether there are narrowings and what their degree is.

Externally, it is sometimes difficult to identify a narrow pelvis, especially grades 1-2. More pronounced narrowings and other deformations are usually visible immediately - in the shape of the woman’s pelvic circumferences, the ratio of waist and buttocks, with short stature (less than 150 cm), with small foot(less than 36), short arms and fingers.

A narrow pelvis is somewhat easier to assume on the eve of childbirth. At the same time, in women with obvious incompatible sizes of the baby and pelvis, the stomach hangs forward, while with compatible parameters it is not so far forward.

Measuring diagonal conjugates

Clinical pelvic discrepancy has no degrees and can be diagnosed even in women with normal parameters. The diagnosis is made only during childbirth after the cervix has fully opened and the fetus should descend - it gradually moves from one position to another inside the cavity of the pelvic bones in order to be born.

If the size of the fetal head is larger than the internal diameter of the entrance to the cavity of the pelvic bones, the child cannot be born through the usual birth canal (cervix and vagina). In this case, childbirth is delayed, the baby begins to suffer in utero, and his death may occur. The only thing the right decision in this case, timely diagnosis and cesarean section. Before the onset of contractions, similar imbalances can be assumed in women:

carrying a fetus weighing more than 4 kg;
with hydrocephalus ( excess fluid in the ventricles of the brain and an increase in the diameter of the head) in the baby;
with an abnormal position of the head in the pelvic cavity - usually with existing bone growths in a woman, rapid labor;
with developmental defects in the fetus that prevent its normal position.

Expert opinion

Daria Shirochina (obstetrician-gynecologist)

No woman is immune from the diagnosis of clinical pelvic discrepancy. The diagnosis is often made by repeated births, despite the successful previous ones. This is due to the fact that the mass of subsequent children is usually larger than the previous ones.

Reasons for the formation of a narrow pelvis

Often, narrowing of the pelvic bones is formed constitutionally in girls. For example, chinese women have smaller pelvic bones and for them a child weighing 3500 g is considered very large, while for Europeans - only with a baby weighing 4000 g. The likelihood of a narrow pelvis is higher in women who have suffered the following diseases:

vitamin D deficiency suffered in childhood (rickets);
poor nutrition;
injuries in the pelvic bones;
bone growths in the area of the pelvic bones, for example, osteomas;
hormonal disorders, in particular, increased levels of male sex hormones, which leads to the formation of a masculine pelvis;
bone infections such as bone tuberculosis, osteomyelitis;
other bone diseases, such as scoliosis.

A. Kyphosis. IN. Lordosis. WITH. Scoliosis.

If a woman has such diseases, the doctor is especially wary of measuring the size of the pelvis during pregnancy.

Pregnancy sizes and degrees

Determined during the initial examination. Knowing the size of the pelvis during pregnancy, the doctor can plan the method of delivery of the woman and pre-hospitalize those who have a narrow pelvis. Variants of anomalies are identified bony pelvis by its shape, as well as by changes in basic dimensions.

The following distances are measured:

spinarum - between the most protruding parts iliac bones;
trochanteric - between the lateral processes (trochanters) femur, the biggest size;
cristarum - between the iliac crests;
external conjugate - between the fossa at the top of the sacrum and the symphysis of the pubic symphysis;
internal conjugate - determined during vaginal examination, this is the distance from the lower connection of the symphysis to the promontory of the sacrum, normally at least 11 cm.

Based on these parameters during pregnancy, the degree of narrowing of a woman’s narrow pelvis is determined when one of the sizes is reduced:

the first - 2 cm from the norm or with an internal (true) conjugate from 9 cm;
the second - by 2-4 cm or with an internal conjugate of 7 cm;
third - by 4-6 cm or at true conjugate between 5 and 7 cm;
fourth - more than 6 cm or with an internal conjugate less than 5 cm.

The first and second and second degrees of narrowing are more common, the third and fourth - only with serious diseases of the bone tissue or general underdevelopment of the girl’s skeleton.

According to the shape of the internal entrance to the small pelvis (from the side abdominal cavity) allocate the following types pelvis:

normal - the shape of the entrance to the pelvic cavity has a regular ovoid shape, which corresponds to the shape of the baby’s head;
simple flat - in this case the longitudinal dimensions of the pelvis are reduced, the sacrum seems to protrude into the cavity;
transversely narrowed - the transverse dimensions are reduced, while the distance from the sacrum to the pubis is normal;
generally uniformly narrowed - with all sizes reduced by the same amount, this is the most favorable of all types;
oblique - occurs after injuries, diseases of bone tissue, while the pelvic cavity has unpredictable dimensions;
osteomalatic - the most unfavorable option, which forms after suffering severe rickets, is extremely rare today.

The influence of a narrow pelvis on pregnancy and childbirth

Gestation in a woman with a narrow pelvis occurs, as a rule, without significant deviations. The only thing women can note:

lower back pain is more pronounced due to a sagging belly;
movements of the child in atypical places - not in the right hypochondrium, but on the right or left below, which is associated with frequent abnormal positions of the fetus due to narrowing of the pelvis.

Otherwise, if the woman is somatically healthy, there are no special features.

Diagnosis of contractions is important for labor management. Exactly from timely detection condition and adequate assessment of the situation depends on the prognosis of childbirth, the health of the baby and the woman.

Symphysitis

In women with narrow anatomical narrowings, complications are possible:

discharge of amniotic fluid before contractions begin;
prolapse of the child’s arms, legs and umbilical cord loops due to water leakage;
weak or abnormal contractions;
labor lasting more than 8-12 hours;
injuries to the skull bones and soft tissues of the fetal head, collarbone fractures;
serious injuries to a woman’s birth canal (ruptures up to the body of the uterus, symphysiopathy).

Watch this video about the peculiarities of pregnancy and childbirth in women with a narrow pelvis:

Rules for guiding the expectant mother

Women with anatomical narrowing of the pelvis are hospitalized in the pregnancy pathology department on the eve of childbirth - one to two weeks before. This time is necessary so that after comprehensive examination woman and determining her readiness for childbirth, determine management tactics - allow vaginal birth or perform a planned cesarean section.

Clinical discrepancy is detected only during childbirth at a time when the cervix is open by at least 8 cm. The absence of dynamics of labor within two hours, the estimated weight of the child is more than 4 kg or a decrease in pelvic dimensions are indications for surgery. Management of pregnancy with a narrow pelvis differs only in the tactics of the birth itself and the timing of hospitalization of women.

How to give birth with a narrow pelvis

Every pregnant woman hopes for birth healthy baby. If there are anatomical narrowings or structural features of the pelvic bones, it is important to predict in advance possible complications and be prepared for them.

An elective caesarean section is always performed in the following conditions:

the last and penultimate degrees of narrowing;
detection of bone growths in the pelvis that may impede the passage of the fetus;
changes in the anatomy of the pelvis due to injuries and diseases;
symphysiopathy with rupture in previous births.

In addition, operative delivery is necessary in cases of a combination of a narrow pelvis and:

fetal weight more than 4 kg;
position of the fetus with the pelvic part down;
the presence of scar changes on the uterus after previous operations (removal of fibroids, cesarean section);
with abnormalities in the structure of the uterus;
with intrauterine fetal suffering according to ultrasound results and with green amniotic fluid.

Carrying out a caesarean section

Clinical inconsistency - absolute indication for discontinuation vaginal birth performing a caesarean section, since the birth of a live child in such conditions is impossible.

An anatomically narrow pelvis during pregnancy is not an absolute indication for surgery, and you can also give birth on your own. If the fetus is relatively small and is correctly presented, and the pregnancy is progressing normally, the woman is given this opportunity. However, she is closely monitored and if there are signs of fetal suffering or a threat to the mother's life, an emergency caesarean section is performed.

A narrow pelvis, according to statistics, occurs in 5-7% of girls. This can be either a constitutional feature, or features of nutrition, development, or the result of past diseases and injuries. Timely diagnosis helps to choose the right labor management tactics in each case. Such women have a chance to give birth on their own, but their percentage of cesarean sections is higher.

The size of the pelvis plays a very big role important role during pregnancy. Sometimes the course of labor depends on the pelvis: if it is narrow, then labor may proceed with or end caesarean section. A narrow pelvis occurs in 2-3% of pregnant women, but it is not always an indicator for artificial delivery.

Gynecologists pay great attention to a woman’s pelvis even during registration. Be sure to have it measured and already in the first days of pregnancy you can predict how the birth will proceed. So what are its features? And what to expect if the pelvis turns out to be narrow? Let's try to find answers to these and other questions.

Pelvic dimensions: norm and deviations

Every woman knows perfectly well what a pelvis is. It is conventionally divided into large and small. It is in the large pelvis, towards the end of pregnancy, that the uterus and fetus are accommodated. And if for some reason its wings are not straightened, then the uterus will move forward, as a result the tummy will “stick out” (become pointed). The small pelvis is a kind of birth canal through which the baby will move at birth. It is clear that if the pelvis turns out to be narrow, then the child will have a hard time “making his way” into the light.

How is the pelvis measured? Surely, if this has already been done to you, then you noticed an incomprehensible set of numbers on your card. If they look like this: 26-29-31-21, then there is nothing to worry about: your pelvis is normal. If any of the indicators is 2 numbers less, then you will be diagnosed with a narrow pelvis. What do these numbers represent? Regular sizes. For example, the interosseous size (the distance between the upper corners of the protruding bones) should be from 25 to 26 cm and so on. All measurements are carried out using a tazometer and a centimeter tape. By measuring the large pelvis from the outside, you can guess what the small pelvis will be like. The size of the latter can be determined by vaginal examination, and you may also be prescribed radiography and ultrasound to determine the size of the pelvis. Also, other factors indicate the narrowness of the small pelvis: hand length is less than 16 cm, shoe size is less than 36, height is less than 160 cm. When measuring the pelvis, it is imperative to take into account the massiveness of the pelvic bones, using the Solovyov index, i.e. measure the circumference of your wrist and if the size becomes more than 14 cm, then your bones are massive, which means your pelvis will be narrow even with normal values.

However, in reality everything is not so simple. A narrow pelvis has its own varieties and characteristics. Both the course of pregnancy and delivery depend on this.

Anatomically narrow pelvis

This is called a basin in which the main dimensions are smaller by 1.5-2 cm. This can be reduced by several sizes, or just one. Depending on this, a generally uniformly narrowed, transversely narrowed, simple flat and flat rachitic pelvis is distinguished. In order to confirm the diagnosis of an anatomically narrow pelvis, use additional methods research. This may be a computed tomographic pelvimetry method or an x-ray method. Thanks to them, it is possible to determine the degree of narrowing of the pelvis. Depending on this, an anatomically narrow pelvis of 4 degrees is distinguished. The first is the most common, and fortunately, it is the easiest, considering its effect on the outcome of pregnancy and childbirth.

Unfortunately, it is very difficult to prevent an anatomically narrow pelvis, because many factors influence the formation of the female pelvis. Most often, the causes arise in early childhood. This may be frequent infectious diseases, malnutrition, lack of vitamins, hormonal disorders during puberty. Bone damage due to rickets, poliomyelitis, and tuberculosis leads to pelvic deformation. There are also congenital anomalies of the pelvis, spinal deformities, pathology in the hip joints, injuries and fractures of the pelvis.

Clinically narrow pelvis

Unlike an anatomically narrow pelvis, which is determined already at the beginning of pregnancy, with a clinically narrow pelvis the situation is different. It can only be diagnosed during childbirth, even if the anatomically narrow pelvis was “absent” throughout the entire pregnancy. Clinically, a narrow pelvis does not depend on the size of the pelvis; it is determined by a discrepancy between the fetal head and the mother’s pelvis.

The causes of its occurrence are most often associated with the course of labor. In the first place is post-term pregnancy, as a result of which the bones of the fetal skull become too dense and they are unable to configure themselves. Clinically, a narrow pelvis is also diagnosed with anomalies of labor, incorrect insertion of the head, with tumors of the uterus, and also if there are In other words, you will hear about the diagnosis “Clinically narrow pelvis” only during childbirth, or even after it.

Narrow pelvis and pregnancy

A narrow pelvis has virtually no effect on the course of pregnancy. Just during this period, if we're talking about about an anatomically narrow pelvis, you should be under the supervision of your attending physician. And of course, prepare in advance for upcoming birth, and they can occur with some peculiarities. In the last trimester, a pregnancy with a “narrow pelvis” can be complicated by incorrect position of the fetus. Due to the fact that the baby's head does not press against the entrance to the small pelvis when it is too narrow, expectant mother shortness of breath often appears.

But even if your pelvis turns out to be “normal,” you shouldn’t relax. You have read the information about a clinically narrow pelvis. In this case, much depends on the expectant mother herself. For example, food. After all, it may not be beneficial for your pelvis and baby. In any case, the nutrition of a pregnant woman should be rational. Doctors also advise every pregnant woman to work on the elasticity of the perineal muscles. For this you may also need... regular sex.

Narrow pelvis and childbirth

The course of labor with a narrow pelvis largely depends on the professionalism of doctors and, naturally, on the woman in labor herself. Many people believe that a narrow pelvis always means a caesarean section. However, practice shows that natural childbirth with this diagnosis is also possible. Naturally, the risk of complications increases significantly. Eat high probability when a child may be born in a state of asphyxia, it may be impaired cerebral circulation, cranial and spinal injuries also occur.

Usually with a narrow pelvis labor activity very weak, labor lasts for a long time, amniotic fluid is discharged prematurely. Loss of the umbilical cord loop is often observed, postpartum infection is possible, and the threat of uterine rupture increases.

But, despite the gloomy forecasts, there is no need to despair. When diagnosed with a narrow pelvis, you simply need to find good specialist and completely trust the professionals.

Believe me, nothing will darken the unspeakable joy of meeting a little man who will become the center of your universe.

Especially for- Tanya Kivezhdiy

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

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

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

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, including 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 occurs, and androgens determine bone growth in length and accelerate the fusion of the epiphyses of the bones. In patients with excess production of androgens, the following forms of the pelvic inlet can be distinguished: longitudinal-oval, round, transverse-oval with normal or increased direct dimensions of the pelvis. A characteristic feature of these forms of the pelvis is a narrow pubic arch.

At present, it is impossible not to take into account the importance of acceleration in the formation of a transversely narrowed pelvis: due to the rapid growth of the body in length, the increase in transverse dimensions does not occur quickly enough. Most authors note: the shape of the pelvis is a sensitive indicator of the dynamics of sexual development. There is a relationship between the beginning puberty and the corresponding shape of the woman’s pelvis.

Professional sports can have a significant impact on the formation of the bone pelvis. Excessively intense, long-term physical activity on certain muscle groups during the development of a girl’s body, when systematically practicing the same sport, leads to a change in the normal proportions of the body. The incidence of anatomically narrow pelvis among female athletes is 64.1%, it is highest among gymnasts (78.3%), skiers (71.4%), and swimmers (44.4%).

Pelvic deformation in adults can occur as a result of bone tumors, osteomalacia, and trauma.

Many classifications of the narrow pelvis have been proposed. Most authors consider it advisable 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 size of the true conjugate.

Classification of anatomically narrow pelvis (according to the shape of the narrowing)

A. Common forms of the pelvis.

1. Generally uniformly narrowed pelvis.

2. Transversely narrowed pelvis.

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

B. Rarely occurring forms of the pelvis.

1. Obliquely displaced (asymmetrical).

2. Pelvis narrowed by exostoses and tumors.

3. Generally narrowed flat pelvis.

4. Other forms of narrow pelvis.

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

The prevalence rate has changed significantly various forms narrow pelvis. The most common form is uniformly narrowed (40-50%). A flat pelvis is less common -

0 degree of pelvic narrowing is usually judged by the size of the true conjugate.

Classification of anatomically narrow pelvis (by 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 - transverse size of the entrance 12.4-11.5 cm;

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

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

III degree - 0.2-0.3%.

In modern conditions, there are no sharp degrees of narrowing of the pelvis, but more and more often erased forms are being discovered, a combination of small degrees of narrowing of the pelvis and large fetuses, as well as unfavorable presentations and insertions of the fetal head. IN last years obstetricians pay attention to significant changes in the structure of various forms of anatomical narrow pelvis.

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

Rice. 71. Caldwell and Moloy classification

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

Android type(20% of all pelvises) - male pelvis. There is a wedge-shaped entrance, a narrow pubic angle, the sacrum is insufficiently curved, and deviated anteriorly. The pelvis narrows funnel-shaped downwards. Noted male type woman's physique: broad shoulders, thick neck, waist not defined. With this form of the pelvis there is greatest number pathology.

Anthropoid type(20-22% of all pelvises) 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. The physique features of such women are: tall, lean, broad shoulders, narrow waist and hips, long, thin legs.

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

Foreign manuals provide two classifications of anatomically narrow pelvises. 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, platypeloid.

diagnostics 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 diagnosing a narrow pelvis great importance have medical history data, primarily about infectious diseases that contribute to delayed development of the girl’s body, the emergence 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 with subsequent lameness.

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

injuries, injuries to the fetus and mother, body weight of newborns, health status of children in the future).

In the diagnosis of a narrow pelvis, an important place is given to objective research methods. During the examination, the general physical development of the pregnant woman is assessed, her height and body weight, and 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 women and becomes saggy in multiparous women.

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

The true conjugate is calculated:

Along the diagonal conjugate;

On the outer conjugate;

By vertical size Michaelis rhombus;

According to Frank's size;

Using X-ray pelviometry;

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 wrist joint with calculation of the Solovyov index.

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

Hypoplastic pelvis differs from normal only in its miniature size while maintaining the outlines and relationships of the bones inherent in a normal pelvis. This pelvic shape is typical for short peoples.

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

The arch is narrow, the sacrum is curved and located vertically far posteriorly between the ilia. The promontory is located high and protrudes slightly under the sacral cavity. For this reason, the entrance to the pelvis is not transversely oval, but round or even longitudinally oval. Women usually exhibit other signs of infantilism: short stature, insufficient development of the external genitalia, mammary glands, pubic hair, armpits and etc.

Male pelvis. Found in tall women strong build 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.

Pelvis of dwarfs. Characterized by a lag in bone development. The pelvis is usually proportional to the torso.

Transversely narrowed pelvis characterized by a decrease in the transverse dimensions of the small pelvis with normal or increased direct dimensions. The sacrum is often flattened. Identification of such a pelvis conventional methods difficult. 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 standing of the promontory, reduction in the transverse size of the pelvic outlet and the transverse size of the sacral rhombus. A classification of transversely narrowed pelvises has been proposed, based on the transverse size of the pelvic inlet (according to X-ray pelviometry): I degree of narrowing - 12.4-11.5 cm; P - 11.4-10.5 cm; III - less than 10.5 cm.

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

The following pelvic variants have been identified.

1. With an increase in all direct dimensions (55%).

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

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

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

the entrance to the pelvis is sharply shortened as a result of the deep retraction of the sacrum into the pelvis, the promontory protrudes into the pelvic cavity much more sharply than normal. The sacrum is flattened and rotated with its base anteriorly and its apex posteriorly. The coccyx is beak-shaped and bent anteriorly. The shape of the iliac bones has also changed: their wings are poorly developed, the crests are deployed, as a result of which the distances Spinarum And Cristarum almost equal. The pubic arch is wide and low. The direct size of the entrance is increased, the transverse size is normal. The pelvis is widened, shortened, flattened, and thinned. Its dimensions: 26-27-31-17 cm. Sacral rhombus - with a reduced vertical size, may resemble a triangle.

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

Determining the position and presentation of the fetus is also important. With a narrow pelvis, oblique, transverse position of the fetus, and breech presentation are more common. Before birth, the presenting head of the fetus 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 pelvic capacity 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 X-ray pelviometry. It is recommended to be performed at 38-40 weeks of pregnancy or before the onset of labor. This method allows you to determine all the diameters of the small pelvis, shape, inclination of the pelvic walls, shape of the pubic arch, degree of curvature and inclination of the sacrum.

Ultrasound has become widespread over the past two decades. The use of ultrasound scanning to diagnose an anatomically narrow pelvis is reduced to obtaining the size of the true conjugate and biparietal size fetal head.

course of pregnancy

The adverse effect of a narrowed pelvis on the course of pregnancy is felt only in its last months. In primiparous women due to

spatial discrepancies 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. A high position of the head entails a number of other complications. A high position of the diaphragm and limited excursion of the lungs 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) rupture of water, which contributes to the possible development of infection in the uterus and fetal hypoxia.

Complications during pregnancy:

Premature rupture of water;

Malposition;

Fetal hypoxia;

Loss of small parts of the fetus.

MANAGEMENT OF PREGNANT WOMEN WITH NARROW PELVIS

Pregnant women with a narrow pelvis should be specially 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 and the size of the pelvis. A labor management plan is developed and possible routes of delivery are clarified. Post-term pregnancy is extremely undesirable. If a pregnant woman has a narrow pelvis and other complications (age, post-term pregnancy, breech presentation of the fetus, etc.), delivery can be performed by a planned cesarean section.

Features of the course of labor:

Early rupture of water;

Loss of small parts of the fetus;

Clinically narrow pelvis;

Trauma to the mother (urogenital fistula, uterine rupture) and fetus, bleeding in the third and early postpartum period.

COURSE AND COMPLICATIONS OF THE 1ST STAGE OF LABOR

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

Nenia - early rupture of water, which can lead to prolapse of the umbilical cord and 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 1ST STAGE OF LABOR

Currently, active expectant management of labor is generally accepted. During childbirth, cardiac monitoring is desirable. The tactics of labor management with a narrow pelvis are determined individually, taking into account all the data objective research, degree of pelvic narrowing and prognosis for the woman in labor and the fetus. Childbirth through the natural birth canal can occur: normally; with difficulties, but end happily if the right help is provided; with complications dangerous to the life of the mother and fetus. With I and II degrees of pelvic narrowing, the outcome of labor depends on the size of the head, its ability to shape, presentation and the nature of insertion, and the intensity of labor. It should be noted that with the first degree of pelvic narrowing, delivery of a full-term fetus is possible provided that the fetus is of average size, has a good head configuration, good labor and the labor mechanism corresponds to the shape of the pelvic narrowing.

With stage II pelvic contraction, delivery of a full-term fetus is possible in some cases, but with a high risk to the life of the fetus and the health of the mother. Mainly the feasibility of childbirth through the birth canal depends on the size of the fetal head, i.e. clinical compliance.

With the third degree of pelvic narrowing, delivery of a full-term fetus through the natural birth canal is possible only after a fetal destruction operation. If the fetus is alive, only cesarean section is indicated.

IV degree of narrowing - an absolutely narrow pelvis. Childbirth through the natural birth canal is impossible even after fetal destruction surgery. The only method of delivery is caesarean section. Currently, III and IV degrees of narrowing are extremely rare.

A fetus during childbirth with a narrow pelvis often suffers from intrauterine hypoxia, which occurs approximately three times more often than with a normal pelvis.

The leading cause of death in children is intrauterine hypoxia and intracranial trauma. When the fetal head stands in one plane for a long time, cardiac activity is disrupted in almost all fetuses.

Currently perinatal mortality with a narrow pelvis it decreases, which is associated with an increase in the frequency of cesarean sections and with improved intensive care for newborns.

Which option the birth will take can often be decided only during the birth itself, i.e. when conducting a functional assessment of the pelvis. Therefore, childbirth is carried out expectantly until signs of a clinically narrow pelvis are revealed. The degree of discrepancy between the head and pelvis of the mother is judged by the following criterion: the absence of forward movement of the fetus along the birth canal (insertion of the head into the pelvis) with good labor activity. The discrepancy between the fetal head and the mother's pelvis can be detected using the Vasten method (V.A. Vasten - Russian scientist).

Vasten's sign is positive: when the obstetrician's palm moves from the plane of the pubis to the head, it is noted that there is an “overhang” of the head, i.e. the plane of the head is above the pubis. The head does not correspond to the mother's pelvis.

Vasten's sign is weakly positive (level): the plane of the pubis and 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 womb - the head corresponds to the mother's pelvis.

REASONS FOR NONCONFORMITY

HEAD OF THE FETUS AND PELVUS OF THE MOTHER

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

2. Incorrect insertion of the head - high straight position of the sagittal suture, anterior cephalic or frontal insertion (23%).

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

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

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

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

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

1. The 1st moment of the biomechanism of childbirth - 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 during the transition from the wide part of the pelvic cavity to the narrow one (where flexion normally occurs). A vaginal examination reveals that the small fontanelle is located along the axis of the pelvis, being the leading point in childbirth.

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

4. 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 outlet of the pelvis with the cutting in of the head; in this case, the sagittal suture becomes straight, and a fixation point is formed - the suboccipital 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 outlet of the pelvis through the eruption and birth of the head.

6. 5th moment - internal rotation of the shoulders occurs as usual.

Features of the biomechanism with a transversely narrowed pelvis

Asynclitic insertion of the head into one of the oblique dimensions of the pelvic inlet plane, and with increased direct dimensions of the pelvis, the head is inserted with a sagittal suture into the straight dimension of the pelvic inlet, which is called the high straight position of the sagittal suture.

At transversely narrowed pelvis, the mechanism of childbirth may not differ from normal. With mild degrees of discrepancy, the most characteristic mechanism of labor is oblique asynclitic insertion of the head (see above). When a transverse narrowing of the pelvis is combined with an increase in the true conjugate, a high, straight position 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 pelvis, the biomechanism of childbirth consists of the following points: 1) flexion of the head at the entrance to the pelvis; 2) extension of the head at the outlet of the pelvis, i.e. no internal

gates; 3) internal rotation of the shoulders, birth of the fetus. If the head does not fit, a clinically narrow pelvis is determined and a cesarean section is performed.

BIOMECHANISM OF BIRTH 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 dimension of the pelvic inlet in a state of moderate extension; the sagittal suture can be located asynclitically. Anterior parietal asynclitism is most often observed.

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

Back to top labor head, as a rule, is mobile 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 first feature of childbirth. 2nd - prolonged standing of the head at the entrance to the pelvis (especially with a rachitic pelvis). The 1st moment of the biomechanism is extension of the head, the leading point is the large fontanel. The formation of asynclitic insertion of the head is the 3rd feature. Anterior asynclitism is usually observed, in which the anterior parietal bone descends below the posterior one, located on a protruding promontory. The sagittal suture is located closer to the cape, remaining so until a pronounced configuration of the head appears. After this, the posterior parietal bone slides off the promontory and 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, resting on the pubic symphysis, contributes to a more pronounced and longer-lasting configuration of the head, which often leads to birth trauma for the woman in labor and the fetus. If the head passes into the plane of the entrance to the pelvis, then with a simple flat pelvis it often remains in a state of extension, and labor proceeds according to the type of birth in the anterior cephalic presentation: internal rotation to the posterior view, formation of the 1st point of fixation (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. 18.

Table 18

Features of the biomechanism of childbirth with a flat-rachitic pelvis

Options for inserting the head in a flat-rachitic pelvis.

1. Synclitic insertion of the head.

2. Asynclitic insertion of the head.

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

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

In a flat-rachitic pelvis, after entering the pelvis, “assault” movements may be observed. rapid labor. And the biomechanism can follow the type of birth in the anterior head or in occipital presentation, i.e. the head in the plane of the narrow part will perform flexion, rotation, at the exit - extension, etc. Due to the prolonged standing of the head and the presence of obstacles, a sharp configuration of the head occurs with the formation birth tumor in the area of the large fontanel (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 predominates: flattening or narrowing. The biomechanism of labor is often mixed, and its course is usually severe.

COURSE AND CONDUCT OF THE PERIOD OF EXILE

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

The main complications of the exile period should be considered:

Weakness of labor (secondary);

Rupture of the uterus in the lower segment when it is overstretched against the background of a discrepancy between the head and pelvis and strong labor;

Possible pinching of soft tissues with the subsequent formation of genitourinary and enterogenital fistulas when the head stands in one plane of the pelvis for a long time;

Injuries to the joints and nerves of the pelvis.

In the second stage of labor it should be carried out functional assessment pelvis During prolonged labor, a large birth tumor appears on the baby’s head, and a cephalohematoma may also appear.

clinically narrow pelvis

Clinically narrow pelvis is a concept associated with the process of childbirth. All cases of discrepancy between the fetal head and the woman's pelvis, regardless of its size, should be classified as a clinically narrow pelvis. If in recent years there has been a decrease in the incidence of an anatomically narrow pelvis, especially pronounced degrees of narrowing, then the incidence of a 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 births with a large fetus.

The reasons for the discrepancy between the mother's pelvis and the fetal head can be different: a slight 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 pelvic sizes (23.7%); large fetal sizes with normal pelvic sizes (10%); sudden anatomical changes in the pelvis (6.1%) and other reasons (0.9%); and in post-term pregnancy - insufficient configuration of the head.

Diagnostic signs of a clinically narrow pelvis:

Prolonged standing of the fetal head in one plane and lack of advancement in the second stage of labor;

Pronounced configuration of the head and birth tumor;

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 anterior view!);

Involuntary straining and the appearance of symptoms of impending uterine rupture.

Signs of a clinically narrow pelvis can be diagnosed when:

Opening of the cervix more than 8 cm;

Absence of amniotic sac;

Empty bladder;

Normal contractile activity uterus.

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

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

Obstetric tactics for the development of a clinically narrow pelvis - emergency delivery by cesarean section!

Thus, childbirth with a narrow pelvis occurs through the natural birth canal if there is a correspondence between the fetal head and the mother’s pelvis.

Indications for planned caesarean section.

1. Narrowing of the pelvis III-IV degree.

2. Narrowing of the pelvis I and II degrees in combination with a large fetus, breech presentation, post-term pregnancy.

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

4. Scar on the uterus.

5. Presence of genitourinary and enterogenital fistulas.

6. Incorrect position of the fetus.

To relieve pain during labor with a narrow pelvis, inhalational anesthetics are used, and antispasmodics are widely used. During childbirth, fetal hypoxia is repeatedly prevented (glucose, sigetin, cocarboxylase, oxygen). In order to prevent perineal ruptures and speed up labor, an episiotomy is often required.

At the end of the second stage of labor, bleeding is prevented (methylergometrine intravenously).

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

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

Imposition during childbirth with a narrow pelvis obstetric forceps or vacuum extraction of the fetus are very undesirable.

In the afterbirth and early postpartum periods with a narrow pelvis, bleeding often occurs due to impaired placental abruption, uterine hypotension, which can be caused not only by complications in the first and second stages of labor, but also (in some cases) by general etiological causes of obstetric bleeding and narrow pelvis

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

In case of a burdened obstetric history and the threat of bleeding, it is recommended to administer intravenous drips of oxytocin with glucose or saline solution within 2 hours after birth.

In the late postpartum period, if labor is managed incorrectly with a narrow pelvis, postpartum infectious diseases, genitourinary and enterogenital fistulas, and damage to the pelvic joints can occur.

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

During the period of “interesting situation”, the dimensions of the pelvis play a very important role, because the specialist, based on them, chooses delivery tactics. If the pelvis is narrow, complications may occur during childbirth. In some cases, natural childbirth is not possible at all. The only way to give birth to a child (if a narrow pelvis is diagnosed during pregnancy) is a caesarean section.

What kind of pelvis do doctors consider narrow and how do they determine it? How will pregnancy proceed with this diagnosis? Let's try to find answers to all these questions.

A little bit of anatomy: the female pelvis

Every person knows perfectly well such a part of the skeleton as the pelvis. It is conventionally divided into small and large. The large pelvis of a pregnant woman houses the uterus and fetus.

The small pelvis is the birth canal. The baby is positioned head down towards the pelvic opening at 7-8 months of pregnancy. With the onset of labor, the fetus enters the pelvis.

The birth of a baby is a rather complex process. The fetus makes various movements in order to adapt to the shapes and sizes of the passage. Before birth, the baby's head is pressed to the chest.

It then turns to the left or right when wedged into pelvic inlet. After this, the head makes another turn. Thus, the child, passing through the pelvis, changes the position of the head twice.

It is worth noting that the head is the largest part of the baby. Its passage along the birth canal is ensured by:

contractile movements of the uterine muscles that push the baby forward;
mobility of the bones of the fetal skull, which are not completely fused and are capable of shifting slightly and thereby adapting to the size of the passage;
easy movement of the pelvic bones.

The dimensions of this part of the skeleton are different for each woman. Some people's pelvis may be normal, some may be narrow, and some may be wide. Narrow variety - serious problem for pregnant women, since the process of giving birth to a child in this case is not easy.

Due to this anatomical feature, childbirth can be complicated. Women with a narrow pelvis most often give birth not naturally, but through a caesarean section.

Anatomically narrow pelvis during pregnancy

Anatomically, a narrow pelvis is considered to be that part of the skeleton, all dimensions of which (or one of them) differ from normal parameters by 1.5-2 cm. About 6.2% of pregnant women have this diagnosis. The peculiarity of the anatomical deviation is that the fetal head may not pass through the pelvic ring during childbirth. Natural childbirth is only possible if the child is very small.

A narrow pelvis may be a consequence of the influence of certain causes on the human body in childhood: frequent infectious diseases, malnutrition, lack of vitamins, hormonal disorders during puberty. The pelvis can be deformed due to bone damage due to polio, rickets, and tuberculosis.

There is a classification of the narrow pelvis by shape. The most common types are:

flat pelvis (flat rachitic; simple flat; with a reduced direct dimension of the plane of the wide part of the pelvic cavity);
transversely narrowed pelvis;
generally uniformly narrowed pelvis.

Rarely encountered forms include:

oblique and obliquely displaced pelvis;
pelvis deformed due to fractures, tumors;
other forms.

The classification based on the degree of narrowing of the pelvis is of great importance:

true conjugate more than 9 cm, but less than 11 cm - 1 degree;
true conjugate more than 7 cm, but less than 9 cm - degree 2;
true conjugate more than 5 cm, but less than 7 cm - 3rd degree;
true conjugate less than 5 cm - 4th degree.

If a woman is diagnosed with 1st degree of contraction, then natural childbirth is quite possible. They are allowed under certain conditions and with 2 degrees of pelvic narrowing. The remaining varieties are always . Attempts to give birth on your own are excluded.

Clinically narrow pelvis during pregnancy

Experts also distinguish a clinically narrow pelvis. Its size is not smaller than normal. It has absolutely normal physiological dimensions and shape. However, the pelvis is called narrow due to the fact that the fetus is large. For this reason, the baby cannot be born naturally.

This type of narrow pelvis is caused not only by the large size of the fetus, but also by incorrect insertion of the child’s head (the largest size). This also prevents the birth of the fetus.

Basically, this type of narrow pelvis is diagnosed during childbirth, but assumptions often arise during last month pregnancy. The doctor can predict the course of labor by analyzing the size of the fetus, which is detected during an ultrasound, and the size of the woman’s pelvis.

Complications that may occur during childbirth with clinical form narrow pelvis, are quite heavy for both the mother and her unborn child. For example, there may be the following consequences: oxygen starvation, respiratory failure, intrauterine fetal death.

How to determine a narrow pelvis in a pregnant woman?

A narrow pelvis in a pregnant woman should be diagnosed long before birth. Women with pronounced narrowing 2 weeks before the expected date of birth are routinely hospitalized in maternity ward to avoid possible complications.

How to determine a narrow pelvis? The parameters of this part of the skeleton are determined by the gynecologist during the first examination when registering with the antenatal clinic. He uses a special tool for this - pelvisometer. It looks like a compass and is equipped with a centimeter scale. The pelvis meter is designed to determine the external dimensions of the pelvis, the length of the fetus, and the size of its head.

Suspicion of a narrow pelvis may arise before examination. As a rule, women with such anatomical feature you can notice a male build, short stature, small foot size, short fingers. Orthopedic diseases (scoliosis, lameness, etc.) may occur.

How is a woman examined by a gynecologist? First of all, the specialist pays attention to the Michaelis rhombus, located in the lumbosacral region. The pits above the coccyx and on the sides are its corners. The longitudinal size is normally about 11 cm, and the transverse size is 10 cm. Parameters of a rhombus, which are smaller normal values, and its asymmetry indicate an abnormal structure of the female pelvis.

A gynecologist, using a tazometer, determines the following parameters:

distance between the iliac crests. The normal value is more than 28 cm;
the distance between the anterior iliac spines (interspinous size). The normal parameter is more than 25 cm;
distance between large skewers femurs. Normal value is 30 cm;
the distance between the upper edge of the pubic symphysis and the suprasacral fossa (external conjugate). The normal parameter is more than 20 cm;
the distance between the symphysis pubis and the promontory of the sacrum. Obstetricians call this parameter a true conjugate. Its value is determined during a vaginal examination. Normally, a gynecologist cannot reach the promontory of the sacral bone.

Some women have massive bones. Because of this, the pelvis may appear narrow even though all its parameters do not deviate from normal values. To assess bone thickness, the Solovyov index is used - the circumference of the wrist is measured. Normally, it should be no more than 14 cm. The pelvis of a pregnant woman may be narrow if the circumference of the wrist is more than 14 cm.

An assessment of the size of the narrow pelvis can also be made during ultrasound examination(ultrasound). Very in rare cases X-ray pelviometry is performed. This study is undesirable for the fetus.

The doctor prescribes it only if there is strict testimony, which include the following:

the age of the pregnant woman is over 30 years (provided that this is her first pregnancy);
high risk of perinatal pathology:
unfavorable outcome of childbirth in the past (stillbirth, surgical delivery through the birth canal, weakness of labor);
endocrine pathology (pituitary adenoma, hyperprolactinemia, hyperandrogenism);
history of miscarriage and infertility;
concomitant extragenital diseases;
suspicion of anatomical changes in the pelvis - previous polio and rickets, congenital dislocations hip joints, narrowing of the external dimensions of the pelvis, the presence traumatic injuries in the anamnesis;
suspicion of disproportion between the fetal head and the woman’s pelvis.

X-ray pelviometry is carried out using a low-dose digital radiographic unit.

All of the above is relevant to diagnosing an anatomically narrow pelvis. How does a doctor identify the clinical variety? This diagnosis is made by a specialist during childbirth.

The obstetrician may notice that the baby's head does not descend into the pelvic cavity, despite the fact that contractions are strong, labor is good and the opening of the cervix is complete.

Doctors know specific signs that help identify lack of advancement of the fetal head. When diagnosing a clinical type of narrow pelvis, an emergency caesarean section is performed.

The course of pregnancy with a narrow pelvis

A narrow pelvis during pregnancy leads to the formation of incorrect fetal positions. Breech presentation is quite common. Oblique and transverse presentations of the fetus can also be diagnosed.

In the last trimester, a pregnant woman may notice some features. For example, due to a narrow pelvis, the baby’s head is not pressed against the entrance to the pelvis. This leads to shortness of breath in the woman. In primigravidas with a narrow pelvis, the abdomen has special form- pointed. In multiparous women, the abdomen looks saggy, as the anterior abdominal wall weak.

Childbirth with a narrow pelvis

A pregnant woman, when a narrow pelvis is detected at the stage of registration at the antenatal clinic, is observed in a special way, because complications are possible. Timely detection incorrect position child, prevention of postmaturity, hospitalization in the maternity ward at 37-38 weeks play an important role in the prevention of complications during childbirth.

A narrow pelvis during childbirth is a serious problem for obstetricians and gynecologists, because it is not so easy to decide whether a pregnant woman can give birth naturally.

In resolving this issue, many factors are taken into account:

pelvic dimensions;
presence/absence of any pregnancy pathology;
age of the fair sex;
presence/absence of infertility in the past.

Doctors determine delivery tactics based on the degree of pelvic narrowing. For example, independent childbirth are possible if the fetus is small, its presentation is correct and the narrowing of the pelvis is insignificant.

With the anatomical variety of a narrow pelvis, premature rupture of amniotic fluid. Possible loss of the umbilical cord or parts of the fetal body (arms or legs). Due to the early rupture of amniotic fluid, the process of cervical dilatation slows down.

Infections can also enter the uterine cavity. They are the causes of endometritis (inflammation of the inner lining of the uterus), placentitis (inflammation of the placenta), and infection of the fetus. As a rule, contractions against this background are very painful. The first stage of labor is prolonged in duration.

With a narrow pelvis it is often observed anomaly of ancestral forces, contractile activity muscles of the uterus. During childbirth, rare and weak contractions are observed. The process of giving birth to a child is very delayed, and the mother in labor becomes tired.

The second stage of labor is characterized by the development secondary weakness of labor. There are difficulties in moving the fetal head. Against this background, intense painful sensations, fatigue of the woman in labor. Prolonged standing of the head in one plane leads to irritation of the receptors of the cervix, the lower segment of this organ.

The period of passage of a child through the birth canal is long. If there are significant obstacles to the birth of a baby, violent labor and excessive hyperextension may occur. Bladder, rectum, urethra.

On the part of the expectant mother, a clinically narrow pelvis is a relative condition for cesarean section, but on the part of the fetus it is considered absolute condition, since there is a threat of development severe consequences and the death of a child.

Quite often, pregnant women diagnosed with a clinically narrow pelvis experience untimely release of amniotic fluid. baby's head long time stands in the same plane.

This leads to weakness of labor, the formation of intestinal and genital genitourinary fistulas, injury to the birth canal. Fetal traumatic brain injuries are common. The threat of complications leads to the completion of labor by surgery.

Caesarean section for a narrow pelvis: indications

Indications for surgery for a narrow pelvis can be divided into 2 groups: absolute and relative.

TO absolute indications include:

narrow pelvis grade 3 and 4;
severe pelvic deformities;
damage to the joints and bones of the pelvis in previous births;
pelvic bone tumors.

In all of the above cases, natural childbirth is impossible. A child can be born exclusively through a caesarean section. It is carried out as planned until the onset of labor or with the onset of the first contractions.

TO relative indications Caesarean section includes:

narrow pelvis 1st degree in combination with one or more additional factors:
large fruit;
breech presentation;
post-term pregnancy;
fetal hypoxia;
a scar on the uterus that occurred in the past during a caesarean section;
abnormalities of the genital organs, etc.
narrow pelvis 2nd degree.

In the presence of relative factors, independent childbirth may be allowed. If during birth process If the pregnant woman’s condition worsens and the life of the mother and fetus is threatened, doctors will perform a caesarean section.

In conclusion, it is worth noting that a narrow pelvis and a caesarean section are not a necessary combination. Don't be alarmed if you have been diagnosed with a narrow pelvis. Find yourself a doctor whom you can trust, and then the birth will take place without problems.

I like!

During pregnancy, the size of the pelvis plays an important role. Sometimes the course of labor depends on this. If the pelvic bones are narrow, complications may arise during childbirth or result in a caesarean section. A narrow pelvis is observed in approximately 3% of women during pregnancy, but it is not always an indicator for cesarean section.

When registering for pregnancy, the female pelvis is given Special attention. After measuring it, the gynecologist will be able to predict at the very beginning of pregnancy how the birth will proceed.

Distinguish anatomical And clinical narrow pelvis during pregnancy.

Anatomical narrow pelvis- discrepancy of at least one parameter by 1.5-2 cm or more from normal. It is a consequence of the impact of certain factors on the body in childhood: poor nutrition, frequent infectious diseases, lack of vitamins, hormonal disorders during puberty, congenital anomalies, injuries and fractures. Also, deformation of the pelvic bones can occur as a result of tuberculosis, rickets, and polio.

If a pregnant woman is diagnosed with 1 degree of narrowing out of 4, then giving birth naturally is quite possible. It is also possible to give birth independently with 2 degrees of contraction, but taking into account certain conditions, for example, if the fetus is not large. The remaining degrees (3 and 4) are always an indication for cesarean section.

Clinical narrow pelvis- discrepancy between the fetal head and the parameters of the mother’s pelvis, diagnosed during childbirth. In this case, the pelvis has normal physiological parameters and shape. It is considered narrow because the fetus is quite large or is not presented correctly on the forehead or face. For this reason, the child cannot be born naturally.

Normal pelvic sizes

The pelvis is measured with a special instrument, a pelvis meter, which measures:

The distance between the anterior upper corners of the iliac pelvic bones. Normally it is 25-26 cm.
The distance between the most distant points of the iliac crests. Normally it is 28-29 cm.
The distance between the greater trochanters of the femurs. Normally it is 31-32 cm.
The distance from the middle of the upper outer edge of the symphysis to the suprasacral fossa. Normally it is 20-21 cm.
Michaelis rhombus (lumbosacral rhombus). Normally, its diagonal value is 10 cm, vertically - 11 cm. If there is asymmetry or its parameters are less than normal values, then this indicates an abnormal structure of the pelvic bones.

Additionally, it is possible to obtain data on the parameters of the pelvic bones using the following studies:

X-ray pelviometry. This study is allowed at the end of the third trimester, when all the tissues and organs of the fetus are already formed. Thanks to the procedure, you can find out the shape of the bones and sacrum, determine the direct and transverse dimensions of the pelvis, measure the fetal head and determine whether it corresponds to its parameters.
Ultrasonography . An ultrasound can determine the correspondence of the size of the fetal head with the size of the pelvic bones. The procedure also allows you to find out the location of the fetal head, since in cases of frontal or facial presentation during childbirth, it will need more space.
Solovyov index- measuring the circumference of a woman’s wrist joint, thanks to which you can determine the thickness of the bones and determine the direct size of the cavity of the entrance to the pelvis. Normally, the circumference of the wrist joint is 14 cm. If it is larger, then the bones are massive; if smaller, then the bones are thin. For example, with insufficient external dimensions of the pelvic bones and with a normal Solovyov index, the dimensions pelvic ring sufficient for a child to pass through it.

Childbirth with a narrow pelvis and possible complications

In the antenatal clinic, all pregnant women with a narrow pelvis are specially registered. It is very important, in this case, to determine the date of birth, since post-term pregnancy is extremely undesirable. The woman will be admitted to the maternity hospital in 1-2 weeks. Closer to the due date, doctors will decide on the method of delivery.

During natural birth with a narrow pelvis, there is a high risk of developing complications in the fetus (breathing disorders, oxygen starvation, birth injury, impaired circulation in the brain, fracture of the collarbone, damage to the skull bones and, worst of all, intrauterine death) and the mother (weak labor, premature rupture of amniotic fluid, postpartum infection, threat of uterine rupture).

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