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Pelvic dimensions for natural childbirth. Dimensions of the anatomically narrowed pelvis of various shapes

The narrow pelvis is considered one of the most complex and difficult sections of obstetrics, since this pathology can lead to the development of dangerous complications in childbirth, especially if they are not carried out correctly. According to statistics, anatomical narrowing of the pelvic bones occurs in 1-7.7% of cases, while in childbirth such a pelvis becomes clinically narrow in 30%. If we take the total number of all births, then this pathology accounts for about 1.7% of cases.

The concept of "narrow pelvis"

During the period when the fetus is expelled from the uterus or in the straining period, the child must overcome the bone ring, which is formed by the bones of the small pelvis. This ring consists of 4 bones: the coccyx, the sacrum and two pelvic bones, which are formed by the ischial, pubic and ilium bones. These bones are connected to each other by ligaments and cartilage. The female pelvis, unlike the male, is larger and wider, but has less depth. A pelvis with normal parameters plays an important role in the normal, physiological course of childbirth without complications. If there are deviations in the symmetry and configuration of the pelvis, its size decreases, then the bone pelvis serves as a kind of obstacle during the passage of the fetal head.

In practical terms, two types of narrow pelvis are classified:

a clinically narrow pelvis occurs when there is a discrepancy between the anatomical dimensions of the woman’s pelvis and the size of the child’s head during childbirth (however, even if there is anatomical narrowing of the pelvis during childbirth, a functionally narrow pelvis may not always occur, for example, when the fetus is small, or vice versa, when functional pelvic indicators are normal, but the large size of the baby leads to the development of a clinically narrow pelvis);

an anatomically narrow pelvis is characterized by a narrowing of several or one size by 2 or more centimeters.

The reasons

The causes of a narrow pelvis are different - in the event of a disproportion in the parameters of the pelvic bones of the mother and the head of the baby, or in the presence of anatomical narrowing.

Etiology of the anatomically narrowed pelvis

The following factors can provoke the occurrence of an anatomically narrowed pelvis:

heavy physical work and malnutrition in childhood;

frequent colds, as well as increased physical activity in adolescence;

neuroendocrine pathologies;

late onset of menstruation, violation of childbearing function, failures in menstrual function.

Anatomical narrowing of the pelvis occurs due to such reasons:

dislocations of the hip joints;

excess androgens, hyper- and hypoestrogenism;

disturbed mineral metabolism;

professional sports (swimming, gymnastics, licking);

psycho-emotional stress and stressful situations that provoke the occurrence of "compensatory hyperfunction of the body", resulting in the formation of a transversely narrowed pelvis;

acceleration (rapid growth of the body in length against the background of a slow increase in transverse pelvic parameters);

damaging factors that affected the fetus in the antenatal period;

tumors and exostoses of the pelvis;

polio;

heredity and features of the constitution;

cerebral palsy;

curvature of the spine (fractures of the coccyx, scoliosis, kyphosis, lordosis);

fractures of the pelvic bones;

bone tumors, bone tuberculosis, osteomalacia;

lag of sexual development;

infantilism, both sexual and general.

Etiology of a functionally narrow pelvis

The disproportion between the maternal pelvis and the head of the child during childbirth is caused by:

preposition of the pelvic end;

atresia (narrowing) of the vagina;

neoplasms of the ovaries and uterus;

pathological insertion of the head (frontal insertions, asynclitism);

malposition;

difficulty in the process of configuration of the bones of the child's skull (with true overwear);

large weight and size of the fetus;

anatomical narrowing of the pelvis.

Childbirth, which is complicated by a clinically narrow pelvis, ends with a caesarean section in 9-50% of cases.

Narrow pelvis: varieties

There are many classifications of the anatomically narrowed pelvis. Quite often, in obstetric literature, a classification is presented, which is based on morphoradiological signs:

Gynecoid type

It makes up about 55% of the total number of pelvises, is a normal type of female pelvis. The physique of the future mother of the female type, thin waist and neck, wide hips, height and weight are within the average.

android pelvis

It is a male pelvis and occurs in 20% of cases. The woman has a masculine physique, namely, the lack of expression of the waist, a thick neck against the background of narrow hips and broad shoulders.

Anthropoid pelvis

Inherent in primates and accounts for about 22% of cases. This form is distinguished by an increase in the direct size of the entrance, which significantly exceeds the transverse size. Women with this configuration of the pelvis are tall, lean, their shoulders are quite wide, while the hips and waist are narrow, the legs are thin and elongated.

Platypeloid pelvis

The shape resembles a flat pelvis and occurs in 3% of women. A woman with such a pelvis has a high stature, pronounced thinness, reduced skin elasticity and underdeveloped muscles.

Narrowed pelvis: forms

Classification of the narrow pelvis according to Krassovsky:

Common forms:

transversely narrowed pelvis (Robertovsky);

generally evenly narrowed pelvis (ORST) - the most common type, which is observed in 40-50% of the total number of pelvises;

flat pelvis, occurs in 37% of cases, is divided into:

a pelvis with a reduced wide part of the pelvic cavity;

flat rachitic;

simple flat (Deventrovsky).

Rare forms:

deformation of the pelvis with fractures, exostoses, bone tumors;

oblique and oblique;

other forms:

assimilation;

osteomalacic;

spondylolisthesis form;

kyphotic form;

funnel-shaped;

common flat.

Degrees of contraction

The classification proposed by Palmov is based on the degree of narrowing of the pelvis:

along the length of the true conjugate (normally 11 cm) refers to a flat pelvis and ORST:

first degree - less than 11 cm, not shorter than 9 cm;

the second degree - indicators of the true conjugate from 9 to 7.5 cm;

third degree - the length of the true conjugate is from 7.5 to 6.5 cm;

fourth degree - an absolutely narrow pelvis, shorter than 6.5 cm.

according to the parameter of the transverse diameter of the entrance of the small pelvis (the norm is 12.5-13 cm), it refers to the transversely narrowed pelvis:

the first degree is the transverse diameter of the entrance to the small pelvis within 12.4-11.5 cm;

the second degree - the transverse diameter of the entrance - 11.4-10.5 cm;

third degree - the transverse diameter of the entrance to the small pelvis is shorter than 10.5 cm.

in terms of the diameter of the wide part of the pelvic cavity (normal 12.5 cm):

the first degree - the diameter is 12.4-11.5 cm;

second degree - diameter less than 11.5 cm.

Dimensions of the anatomically narrowed pelvis of various shapes

Narrow pelvis: size chart in centimeters

	Pelvis shape
	simple flat	flat-rachitic		transversely narrowed	normal
outdoor					25/26-28/29-30/31
External conjugate
Diagonal conjugate
True conjugate
Rhombus Michaelis
vertical diagonal
Horizontal Diagonal
Entry plane
Side conjugate
Transverse

Differential criterion	Reducing direct dimensions in all planes	Reducing the direct size of the plane of entry into the small pelvis	Uniform reduction of parameters (all) by 1.5 cm	Shortening of transverse dimensions	Missing

Diagnostics

A narrowed pelvis is diagnosed and evaluated in a antenatal clinic, on the day of registration of a pregnant woman. To determine the narrow pelvis during pregnancy, the doctor must study the history, perform an objective examination, including a vaginal examination, measurement of the pelvis, palpation of the uterus and pelvic bones, body examination, anthropometry. If necessary, additional research methods can be prescribed: ultrasound scanning and X-ray pelviometry.

Anamnesis

It is important to pay attention and study the living conditions and illnesses of a pregnant woman in childhood (chronic pathology and injuries, intense sports, hard physical work and poor nutrition, hormonal imbalance, bone tuberculosis and osteomyelitis, poliomyelitis and rickets). Obstetric anamnesis data are also important:

whether there was a stillbirth or death of a newborn in the neonatal period;

what was the reason for the operative delivery, whether there were craniocerebral injuries in the fetus during childbirth;

How did previous births go?

Objective research

Anthropometry

Low growth (less than 145 cm) in most cases indicates the presence of a narrowed pelvis. However, the presence of a transversely narrowed pelvis is also possible in tall women.

Evaluation: silhouette, physique, gait

It has been proven that in the presence of a strongly protruding belly forward, the center of the upper body is shifted posteriorly to maintain balance, while the lower back is pushed forward, increasing the lumbar lordosis, as well as the angle of the pelvis.

Assessment of the shape of the abdomen

It is known that primiparous women have an elastic abdominal anterior wall, as a result of which the abdomen acquires a pointed shape. Multiparous women have a sagging belly, since the head at the end of the gestation period is not inserted into the entrance of the pelvis (narrowed), while the uterine fundus is high, and the uterus itself has a deviation anteriorly and upward from the hypochondrium.

Feeling of the Michaelis rhombus and inspection.

Identification of signs of virilization and sexual infantilism.

Rhombus Michaelis is formed by such anatomical formations:

on the sides - the upper posterior protrusions (or spines) of the iliac bones;

below - the top of the sacrum;

above - the lower border of the fifth lumbar vertebra.

Pelvic palpation

During palpation of the iliac bones, their location, contours and sloping are determined. During palpation of the trochanters (large trochanters of the femur), the presence of an oblique pelvis can be determined if the trochanters are located at different levels and are deformed.

Vaginal examination

Allows you to determine the capacity of the pelvis, evaluate the shape and examine the sacrum, the presence of bone protrusions, the depth of the sacral cavity. It is also possible to determine the deformation of the side walls of the pelvis, to determine the diagonal conjugate and the height of the symphysis.

Pelvis measurement

Main measurements:

the uterus is measured to determine the approximate weight of the fetus;

the height of the pubic joint is set;

the pubic angle is determined (the norm is 90 degrees);

measurement of the pubic-sacral size (the segment is measured from the junction of the second and third sacral vertebrae to the middle of the symphysis). Normally 21.8 cm;

Solovyov index - measurement of the circumference of the wrist at the level of the location of the condyles of the forearm. With the help of this index, the thickness of the bones is determined: a small index is responsible for thin bones, and a large one for thick ones, respectively. The norm is 14.5 - 15 centimeters;

measurement of the Michaelis rhombus (horizontal diagonal 10 cm, vertical diagonal 11 cm). The presence of asymmetry of the rhombus indicates a curvature of the spinal column or pelvis;

external conjugate - measuring the distance from the upper edge of the womb to the upper corner of the Michaelis rhombus. Normally 20 centimeters;

Distantia trohanterica - the segment between the two skewers of the femur, normal - 31-32 centimeters;

Distantia cristarum - the segment between the most distant points of the iliac crests. Normal - 28-29 centimeters;

Distantia spinarum - a segment between the upper anterior projections of the ilium. Normally - 25-26 centimeters.

Additional measurements:

if asymmetry of the pelvis is suspected, the lateral Kerner conjugate and oblique dimensions are determined;

measure the exit of the pelvis;

measure the angle of the pelvis.

Special research methods

X-ray pelviometry

It is allowed to perform X-ray examination only in childbirth or after 37 weeks of pregnancy. With its help, the nature of the structure of the pelvic walls, the size and shape of the pubic arch, the severity of the sacral curvature, the features of the ischial bones are determined, and this method also allows you to determine all the diameters of the pelvis, the size of the fetal head and its position relative to the pelvic planes, the presence of fractures and tumors.

ultrasound

Allows you to determine the size of the head and its localization, the true conjugate, to evaluate the features of insertion into the entrance of the fetal head. With the transvaginal transducer, all required pelvic diameters can be set.

Method for calculating the true conjugate

For this purpose, the following methods are used:

on ultrasound examination of the pelvis;

according to X-ray pelviometry;

according to the Michaelis rhombus: the upper size of the rhombus corresponds to the conjugate index (true);

1.5-2 centimeters are subtracted from the indicator of the diagonal conjugate (if the Solovyov index is 14-16 cm or less, 1.5 cm is subtracted, if the Solovyov index exceeds 16 cm, then 2 cm is subtracted);

9 is subtracted from the size of the outer conjugate (the norm is at least 11 cm).

Features of the course of pregnancy

In the first half of the gestation period, complications in the presence of a narrowed pelvis are not observed. However, the nature of the course of pregnancy in the second half is exacerbated by the influence of the underlying pathology, which led to the formation of a narrow pelvis, while emerging complications (intrauterine infection, preeclampsia) and extragenital pathologies have a certain influence. For pregnant women with a narrow pelvis, it is typical:

high standing of the head against the background of the inability to insert it into the pelvis. This is due to the high standing of the diaphragm and the uterine fundus, causes an increase in heart rate, fatigue and shortness of breath;

quite often, pregnancy can be complicated by premature outflow of amniotic fluid, due to the lack of contact with the pelvic inlet due to the high standing of the head;

significant fetal mobility can cause extensor or breech presentation and incorrect position of the fetus;

increased risk of preterm birth;

the formation of a sagging abdomen in multiparas and a pointed abdomen in primiparas can provoke an asynclitic insertion of the head during childbirth.

Management of pregnancy

All pregnant women with a narrow pelvis are registered with an obstetrician. A few weeks before the onset of labor, a woman must be hospitalized in a planned manner in the antenatal unit. Here the gestational age is specified, as well as the calculation of the estimated weight of the fetus, the pelvis is measured, the presentation of the fetus and its condition are clarified, against the background of the data obtained, the most suitable delivery option is selected (a birth management plan is formed).

The method of delivery is selected based on the history, degree and form of the anatomical narrowing of the pelvis, the approximate weight of the child, as well as other complications of pregnancy. Natural childbirth can be performed in case of prematurity of pregnancy, the first degree of narrowing with a mature cervix and normal fetal size, in the absence of an aggravating history.

Planned operative delivery (caesarean section) is performed in the presence of such indications:

3-4 degree of narrowing of the pelvis (very rare);

a combination of any obstetric pathology requiring a caesarean section and a narrow pelvis;

the birth of a fetus with a birth injury, complications in previous births, a history of stillbirth, age-related women in labor;

a combination of the first or second degree of narrowing with the presence of a large fetus, post-term pregnancy, an anomaly in the position of the child, breech presentation.

Pregnancy and pelvic pain

Pain in the pelvic bones begins to appear after 20 weeks and can be caused by various reasons:

lack of calcium

Aching constant pain that is not associated with a change in body position or movement. It is recommended to take vitamin D in combination with calcium supplements.

Divergence of the pelvic bones and sprain of the uterine ligaments

The larger the size of the uterus, the stronger the tension experienced by the uterine ligaments that hold it, this is manifested by discomfort and pain during walking, as well as at the moments of the baby moving. The provocateurs of the process are relaxin and prolactin, under the influence of which the pelvic cartilage and ligaments swell and soften in order to facilitate the passage of the fetus through the bone ring. To stop such pain, it is recommended to wear a bandage.

Divergence of the pubic joint

Excessive swelling of the symphysis, which is a rather rare pathology, is accompanied by arching pain in the pubic region, and it also becomes impossible to raise the leg while in a horizontal position. This pathology is called symphysitis, it is accompanied by a divergence of the pubic joint. Effective treatment by surgical intervention after delivery.

The course of childbirth

Today, the tactics of conducting labor in the presence of a narrow pelvis implies a significant increase in indications for abdominal delivery, both planned and emergency, in the presence of complications in childbirth. Natural delivery is a very difficult task, since the outcome can be both favorable and unfavorable for both the child and the woman. In the presence of the third and fourth degree of narrowing, the birth of a full-term live baby is impossible - only a planned operation. In the presence of narrowing of the pelvis to the first or second degree, the successful outcome of natural childbirth depends on the parameters of the fetal head, its ability to change, the nature of the insertion and the intensity of labor itself.

Complications in childbirth in the presence of a narrow pelvis

First period

During the opening of the uterine pharynx, such a complication of childbirth may occur:

oxygen starvation of the fetus;

prolapse of small parts or loops of the baby's umbilical cord;

early rupture of amniotic fluid;

weakness of tribal forces (in 10-38% of cases).

Second period

During the expulsion of the fetus through the birth canal, the following complications may occur:

damage to the nerve plexuses of the pelvis;

damage to the pubic joint;

necrosis (death) of the tissues of the birth canal, followed by the formation of fistulas;

birth injury;

the threat of uterine rupture;

intrauterine hypoxia;

development of secondary weakness of tribal forces.

Third period

In the last stage of labor, as well as in the early postpartum period, bleeding may occur, which occurs due to a long anhydrous period and the course of labor.

Birth management

Today, the most correct tactics of conducting childbirth in the presence of such a pathology is active-expectant tactics. At the same time, the tactics of the birth process should be purely individual and based not only on the degree of narrowing of the pelvis and the results of an objective study of the expectant mother, but also on the prognosis for the child and the woman. The birth plan should include the following:

fruit-destroying surgery for intrauterine death of the fetus;

caesarean section with a live fetus and indications for surgery;

preventive measures in the subsequent and early postpartum periods;

identification of signs of the presence of clinical inconsistency;

prevention of infectious complications;

prevention of intrauterine starvation of the child;

prevention of the development of weakness of tribal forces;

bed rest during contractions, which can prevent early discharge of water (the woman should be on the side to which the back of the child is adjacent).

In childbirth, they control the discharge from the genital tract (bloody, water leakage, mucous membranes), urination, the state of the vulva (the presence of swelling). If there is urinary retention, bladder catheterization is performed, however, it should be remembered that such a symptom may indicate an imbalance in the baby's head and the pelvic dimensions of the woman in labor.

The most common complication in childbirth in the presence of a narrowed pelvis is premature rupture of amniotic fluid. In the presence of an "immature" cervix, operative delivery is required. With a "mature" neck, labor-inducing manipulations are indicated (provided that the weight of the child does not exceed 3.6 kg and the first degree of narrowing is present).

In the period of contractions, in order to prevent their weakness, an energy background is required, the woman in labor receives medical sleep-rest in a timely manner. In the course of assessing the effectiveness of labor activity, the obstetrician must control not only the dynamics of the opening of the cervix, but also the nature of the movement of the head through the birth canal.

Induction of labor should be performed carefully, and its duration cannot exceed 3 hours (if there is no effect, a caesarean section). In addition, in the first stage of labor, antispasmodics must be administered without fail (with an interval of 4 hours), for the prevention of hypoxia, the Nikolaev triad is performed and antibiotics are prescribed with an increase in the anhydrous period.

The period of exile may be complicated by secondary weakness, the development of fetal hypoxia, and in the case of a prolonged stay of the fetal head in the birth canal, fistulas may form. Therefore, timely release of the bladder and episiotomy is required.

Disproportions of the pelvis of the woman in labor and the head of the child

The appearance of a clinically narrow pelvis is facilitated by:

abnormal forms of a narrow pelvis;

a large head of a child in the presence of normal pelvic sizes;

incorrect presentation of the fetus or unsuccessful insertion of the head;

large fetus and slight narrowing of the pelvis.

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

in identifying signs of Zangheimester and Vasten (after the discharge of amniotic fluid);

in the diagnosis of a birth tumor of the soft tissues of the head, the rate of its growth and appearance;

assessment of the configuration of the baby's head;

in determining the features of insertion and subsequent assessment of the biomechanism of labor based on insertion data.

Signs of a clinically narrow pelvis:

premature and early outflow of water;

significant head configuration;

protracted course of 1 period;

the emergence of a clinic threat of uterine rupture;

positive signs according to Zanheimester, Vasten;

symptoms of clamping of the urea and soft tissues (the presence of blood in the urine, urinary retention, swelling of the vulva and cervix);

the occurrence of attempts when the head of the fetus is pressed against the entrance to the pelvis;

the head does not advance with sufficiently strong contractions, discharge of water and full opening of the uterine pharynx;

the biomechanism of childbirth is violated, does not correspond to this type of narrowing of the pelvis.

Vasten's sign is determined by palpation (they find out the ratio of the entrance to the pelvis and the baby's head). A negative sign of Vasten is a condition in which the head is inserted into the pelvis, located below the pubic joint (the palm of the obstetrician falls below the womb). The symptom is flush - the palm of the doctor is located at the level of the womb (the symphysis and the head are in the same plane). A positive sign is that the obstetrician's palm is located above the symphysis (the head is above the plane of the womb).

If there is a negative sign, childbirth ends on its own (since the dimensions of the pelvis and head correspond). In the presence of a symptom flush with an adequate configuration of the head and effective labor, childbirth is also independent. With a positive sign, independent childbirth is excluded.

Kalganova suggested using three degrees of discrepancy between the head and pelvic dimensions:

The first degree, or relatively inconsistency.

There is a correct insertion of the head and an adequate configuration. The contractions are of sufficient strength and duration, but the advancement of the head and the opening of the uterus are slowed down, in addition, the discharge of water is untimely. Urination is difficult, but Vasten's sign is negative. As an option - self-completion of childbirth.

Second degree, or major nonconformity.

The insertion of the head and the biomechanism of labor are not normal, the head has a sharp configuration and stays in the same plane for a long time. Urinary retention, anomalies of generic forces (weakness or discoordination) appear. Westen's symptom - flush.

The third degree, or absolute inconsistency.

Premature attempts occur against the background of a complete lack of advancement of the head, even despite the full opening and good contractions. The birth tumor grows rapidly, signs of bladder clamping appear, and there is a threat of uterine rupture. Westen's sign is positive.

The presence of the second and third degrees of discrepancy is an indication for immediate operative delivery.

Case Study

A woman with the first birth (20 years old) was admitted to the maternity hospital complaining of contractions within two hours. There was no outflow of water. The general condition of the woman in labor is satisfactory, the dimensions of the pelvis are 24.5-26-29-20, the circumference of the abdomen is 103 centimeters, the height of the bottom of the uterus is 39 centimeters. The location of the fetus is longitudinal, the head is pressed to the entrance to the small pelvis. Auscultatory: no pain, clear heartbeat. Contractions are of good duration and strength. The approximate weight of the fetus is 4 kg.

In the course of a vaginal examination, it was determined that the cervical dilatation was 4 cm, it had stretchable thin edges, and it was smoothed. The fetal bladder functions normally, the water is whole. The head is pressed, the cape is not available. Diagnosis: pregnancy 38 weeks, the first period of the first birth on time. Transversely narrowed pelvis of the first degree, the fetus is large.

After six hours of active contractions, a second vaginal examination was performed: the cervix was dilated to six centimeters, the fetal bladder was absent. The head is pressed with an arrow-shaped suture in a direct size, the placement of a small fontanel is anterior.

Diagnosis: pregnancy 38 weeks, the first period of the first birth on time. Transversely narrowed pelvis of the first degree, the fetus is large, straight high standing of the sagittal suture.

A decision was made to end the birth by surgical intervention (large fetus, narrowing of the pelvis, incorrect insertion). The caesarean section was performed without complications, the child weighing 4.3 kilograms was removed.

Clinically narrow pelvis during pregnancy - this is the diagnosis that treating specialists make for some expectant mothers. The presence of this pathology often causes various severe outcomes in a woman during childbirth. This is also one of the possible arguments for a planned caesarean section.

Specialists distinguish between a large and small pelvis. The growing uterus is located in the pelvic area. Because of its narrowness, the uterus does not straighten out, so the stomach takes on a pointed shape. During childbirth, the baby moves along the open pelvis. A clinically narrow pelvis during childbirth can become a serious obstacle to the advancement of the fetus and the further outcome of delivery. There are some types of narrowing and features of gestation.

General definitions

Specialists distinguish two types of narrowing: anatomically and clinically narrow pelvis. It is worth distinguishing between these concepts, because they are different. The first term is detected when there is a deviation from the normal size by 2 cm. According to anatomical parameters, the pelvic narrowing is classified as follows:

flat;
General uniform narrowed;
narrowed in the transverse direction.

It is almost impossible to prevent such a pathology.

The main reasons for the development of anatomical pathology include the following points:

Infectious diseases that the representative of the fair half suffered in the past.
Hormonal imbalance in adolescence.
Rickets, tuberculosis or polio that has damaged bone tissue.
Physical stress.

A clinically narrow pelvis during childbirth is detected at the moment when the doctor diagnoses discrepancies between the size of the baby's head and the parameters of the woman's pelvis. This happens during the active phase of labor. Sometimes mothers learn about this feature only after the birth of the crumbs. This pathology can become a companion of mothers who did not even know about such a problem during the entire gestation. There are the following degrees of pathology:

Small discrepancy;
Significant;
Complete mismatch.

The degree is determined taking into account the following important parameters, such as: the nuances of the placement of the head, the absence or presence of movement, the configuration feature.

Causes of a narrow pelvis in pregnant women

Narrowing of the pelvis of the clinical type can develop for the following reasons:

Large pregnancy, that is, more than 4 kg;
Anatomically narrow pelvis;
The transition during gestation, when the baby's head loses its ability to change;
Pathological processes that contribute to an increase in the size of the fetal head;
Neoplasms in the pelvic area (oncology).

Narrow pelvis during pregnancy: signs

During childbirth, a woman may experience the following pathologies, indicating a clinical narrowing:

The head of the baby is not pressed against the pelvic bones;
Violated the natural course of childbirth;
Untimely discharge of amniotic fluid;
Impaired contraction of the uterus;
The appearance of a threat of uterine rupture;
The occurrence of attempts while pressing the fetal head to the entrance to the pelvis;
With the full opening of the uterus, no advancement of the fetus is observed;
Prolonged stay of the head in the pelvic plane;
bladder problems;
The presence of a birth tumor on the baby's head.

During the course of active labor, the baby's heartbeat is constantly measured, it is very important that he does not overwork from protracted labor. During vigorous activity, the doctor notes the exit of the baby's head, note the degree of disclosure of the uterus, the strength of contractions.

If a woman has a clinical narrowing, the classification of which is described above, or the fetus is large enough, then experts strongly recommend doing a caesarean section so that the baby does not die during the birth process or to avoid injury during passage through the birth canal. This is the only way out of the current situation, given the complexity of the situation.

Often, future mothers who have a clinical narrowing during childbirth experience an untimely discharge of water, so the baby's head can stay in the same plane without movement for a long time. All this leads to weak labor activity, the occurrence of intestinal-genital fistulas, craniocerebral injuries in crumbs. A high probability of complications can lead to surgical intervention in labor.

Visual methods of determining

This diagnosis is not made for every woman. Expectant mothers with the following body structure pathologies fall into a special risk group:

If a woman has short brushes, no more than 16 cm;
A small foot size may also indicate the presence of this disorder;
In women of small stature, less than 165 cm, there is a visible curvature of the spine, lameness and other gait disturbances;
The previous labor activity gave certain complications;
The presence of failures during the menstrual cycle;
Women with a masculine body constitution also have a predisposition to a narrow pelvis and subsequent problems during delivery.

Degrees of a narrow pelvis in pregnant women

During the external measurement, the following degrees are noted:

1 degree - deviations from the norm by 10 cm;
2 degree provides for a difference of 8.5-9.9 cm;
Grade 3 is a deviation of 5-8 cm;
4 degree of pelvic constriction - 5 cm or less.

1-2 degree of narrowing of the erased form of narrowing does not interfere with the normal course of gestation. 3 and 4 degrees of narrowing are extremely rare, since they can cause serious disorders in the functioning of the musculoskeletal system.

Bearing a fetus with a slight degree of narrowing

1-2 degrees of narrowing do not have such a pathogenic effect on the development of the fetus as a whole.

Numerous studies have confirmed the following individual characteristics of gestation in patients with a similar diagnosis:

The time of active gestation in most cases is 38 weeks, cases of overcarriage of the fetus are extremely rare;
The occurrence of various complications is up to 80% of all recorded cases;
Future mothers with pelvic narrowing are most often subject to excessive mobility and relaxation of the pelvic joints, accompanied by severe pain and gait disturbance;
The occurrence of pathological shortness of breath is caused by too high a position of the child in the abdomen.

Do not be afraid of such a diagnosis, now you know the individual characteristics of bearing a child with pelvic constriction. There is nothing to worry about here. A slight deviation from the norm in the size of the pelvis for normal childbirth without complications is not terrible, since the sensitive cartilage is stretched during gestation.

Narrow pelvis during pregnancy: diagnosis

An anatomically narrow pelvis can be detected in a future mother in advance, that is, before the onset of childbirth. Expectant mothers with a narrow pelvis are hospitalized a few weeks before the expected date of birth to prevent possible complications. How to identify this pathology?

A narrow pelvis is detected during the first examination, that is, when a woman becomes registered. The specialist uses a special tool for this purpose - a tazometer, it is a kind of compass with a scale. With it, you can clarify the outer dimensions of the pelvis, the length of the fetus, as well as the circumference of the head of the crumbs. When making calculations, the pregnant woman is laid on her side with an open stomach. This procedure involves the clarification of several important parameters:
the distance between the protruding points of the anterior surface of the pelvis, the norm is 26 cm;
length from the remote points of the iliac bones, this value in the normal range is about 29 cm;
the final distance between the skewers of the femur is 31 cm;
length between the points of the upper corner of the cross and the upper edge of the pubic articulation.

Long before such an examination, there may be a suspicion of an anatomically narrow pelvis. The fair sex with this feature has a male constitution of the body, growth is below average, the size of the foot is small. In addition, various orthopedic diseases can develop against this background. The specialist pays special attention to the structure of the bones of a woman, especially the Michaelis rhombus, located in the lumbosacral zone. The dimples above the coccyx are the corners of this rhombus.

A clinically narrow pelvis during childbirth is diagnosed exclusively by a specialist. During delivery, the obstetrician may notice that the baby's head does not descend into the small pelvis, despite good labor activity and full opening. Gynecologists know the exact symptoms of a clinically narrow pelvis; in the diagnosis of this pathology, an emergency caesarean section is performed.

Making a final diagnosis

A few weeks before the expected birth, specialists repeat the pelvic measurements again. It is necessary to do this, because the baby is constantly growing. The estimated size of the child can be found out during a routine examination. The size of the pelvis is measured from the top of the pubis to the highest point of the uterus. It can be felt through the stretched abdominal wall in the later stages of gestation.

Until the onset of labor, a specialist cannot make a diagnosis, he can state a certain discrepancy between the volume of the baby's head and the parameters of the pelvis. Only in this way can a more accurate forecast for childbirth be made.

A similar study is carried out after 38 weeks of gestation. But the final diagnosis can only be determined in the maternity ward. In the emergency room, the indicators of the pelvis and head of the baby are measured again, the slightest changes are monitored.

Childbirth with a narrow pelvis

A pregnant woman with a narrow pelvis is given increased attention, because she may have complications during childbirth. In order to avoid insurmountable complications during delivery, to prevent overbearing, a pregnant woman is hospitalized at 37-38 weeks of pregnancy. The diagnosis of pelvic narrowing is considered a serious task for obstetricians, since in each case it is decided individually: whether the expectant mother should give birth naturally or whether the need for surgery still remains a priority. When making such a serious decision, a number of factors are taken into account:

the exact size of the pelvis;
the presence of any additional pathologies during pregnancy;
the age of the pregnant woman (30 years or more);
the state of the reproductive system (probability of infertility).

Tactics specialist is determined based on the degree of narrowing of the pelvis. Natural childbirth is possible in case of small size of the fetus of correct presentation, with a slight degree of narrowing.

With an anatomical narrowing due to the early outflow of water, the process of opening the uterus may slow down. Also, various dangerous infections can enter the unprotected uterine cavity, which can cause infection of the fetus. Contractions against such a background of infection are too painful, and the duration of labor is delayed.

With a diagnosed narrowing, a pathology of the labor forces is observed, when rare and weak contractions are noted, the process of the child's passage through the canal is delayed, and the woman in labor gets tired. A long stay of the baby's head leads to irritation of the sensitive receptors of the cervix. The period of passage through the birth canal is quite long, against this background, violent labor activity, stretching of the bladder, urethra can develop.

When is a caesarean section necessary?

If a clinically narrow pelvis is found in a future mother, the specialist’s tactic is to perform a caesarean section or allow the mother to have a natural birth. Recommendations for surgery can be relative when a favorable outcome and natural course of childbirth is possible, as well as absolute when an operation is performed. Indications for accurate operation are the following situations:

Diagnosed narrowing of 3 and 4 degrees;
Clearly deformed pelvis;
Damage to the pelvic bones during a previous labor activity;
The presence of bone tumors in the pelvic area.

All of these situations exclude the possibility of natural childbirth. A child can be born only due to a caesarean section, it is planned before the immediate onset of labor or with the appearance of the first contractions.

Relative indications for surgery include the following:

With a diagnosed narrowing of the first degree;
big baby;
Prolongation of pregnancy;
The presence of fetal hypoxia;
Visible scar on the uterus, made during a previous birth;
Anomalies in the development of the organs of the reproductive system;
Identified narrowing of the 3rd degree.

If a pregnant woman has relative indications for surgery, this means that labor is also possible in a natural way. If the condition of the pregnant woman worsens during delivery, if there is a real threat to the fetus and the woman in labor, then another section is also performed on her.

Likely consequences with a narrow pelvis

During the initial period of bearing a baby, the pathology does not affect the course of pregnancy in any way, but closer to the expected date of birth, when the uterus begins to rise due to the narrowness of the pelvis, this feature negatively affects the quality of breathing of the pregnant woman.

Due to the increased mobility of the uterus, the child takes the wrong position. In babies born from a woman with pelvic narrowing, spinal curvature, temporary asphyxia, and circulatory disorders of the brain are formed.

It is very important to listen to a specialist when making a decision: he will be able to give valuable recommendations on how to give birth in your particular case, taking into account all the parameters of the pelvis. If there is a slight risk that the baby may be injured when passing through the birth ring, you should refrain from natural labor. Cesarean section under such a combination of circumstances can be called the best solution for maintaining the health of the baby and facilitating labor.

If a narrowing is diagnosed in a woman while carrying a baby, then specialists will have to determine whether the expectant mother will be able to give birth without surgery or whether a caesarean section will still have to be performed. To this end, a sufficient number of various studies are being carried out, all kinds of measurements are being made so that the possibility of injury to the child and mother during childbirth is completely excluded. The successful birth of a baby directly depends on the level of professionalism of competent specialists and a timely decision.

In the diagnosis of pelvic constriction, natural childbirth can also be used. But at the same time, a specialist observing the course of pregnancy must take into account a lot of nuances before allowing such an enterprise. Among these factors, it is worth noting the course of gestation and the size of the head. A pregnant woman will receive admission to natural childbirth only if several times during pregnancy, and also if during measurements it is revealed that the baby’s head is of suitable size, the baby’s heartbeat is normal, and the stomach does not have a pronounced pointed shape.

With a similar diagnosis, you can also give birth to a completely healthy baby. The bearing of the fetus must be approached with the utmost responsibility. Carrying a baby is that wonderful period of waiting for a miracle, when any mother looks at her lifestyle with more serious eyes. All pregnant women should follow the recommendations of the supervising specialist so that the gestation of the fetus goes smoothly, without any additional complications.

A narrow pelvis is not considered a diagnosis that puts an end to natural childbirth. On the contrary, even in the presence of such a pathology, you can give birth on your own. The female body is a strong vessel in which the bearing and birth of a child is laid. Often, during gestation, the cartilage on the coccyx gradually expands by 2 cm, in many cases this is enough for the natural course of childbirth.

In order to simplify the tactics and behavior of specialists during childbirth, when there is a diagnosis of "narrow pelvis", a protocol has been developed for assisting with the anatomical and clinical form of narrowing of the pelvis. Using the guidance of childbirth with a clinically narrow pelvis, the specialist determines the tactics of delivery.

Not in all cases, the observing specialist decides to carry out artificial delivery, natural labor is also possible. Each case of birth is unique, during active labor, the doctor relies on many objective factors to make the right decision, which will be the best outcome for the mother and child.

1. Transverse diameter, diameter transversa- the distance between the most distant points of both border lines.

2. Oblique diameter, diameter obliqua(dextra et sinistra) - measured from the right (left) sacroiliac joint to the left (right) iliopubic eminence.

3. Diagonal conjugate, conjugata diagonalis- the distance from the lower edge of the symphysis to the most prominent point of the cape of the sacrum. (normally 12.5-13 cm)

The diagonal conjugate is determined during a vaginal examination of a woman, which is performed in compliance with all the rules of asepsis and antisepsis. II and III fingers are inserted into the vagina, IV and V are bent, their rear rests against the perineum. The fingers inserted into the vagina are fixed at the top of the promontory, and with the edge of the palm rest against the lower edge of the symphysis. After that, the second finger of the other hand marks the place of contact of the examining hand with the lower edge of the symphysis. Without removing the second finger from the intended point, the hand in the vagina is removed, and the assistant measures the distance from the top of the third finger to the point in contact with the lower edge of the symphysis with a tazometer or centimeter tape. It is not always possible to measure the diagonal conjugate, because with normal dimensions of the pelvis, the promontory is not reached or can be felt with difficulty. If the cape cannot be reached with the end of the extended finger, the volume of this pelvis can be considered normal or close to normal.

3.1. True conjugate, diameter conjugata- the distance from the posterior surface of the pubic symphysis to the most prominent point of the promontory of the sacrum.

To determine the true conjugate, 1.5–2 cm is subtracted from the size of the diagonal conjugate.

3.2. Anatomical conjugate- the distance from the upper surface of the pubic symphysis to the most prominent point of the promontory of the sacrum.

4. Distantia spinarum- the distance between the superior anterior iliac spines. (normally 25-26 cm)

5. Distantia trochanterica- the distance between the greater trochanters of the femur. (normally 30-31 cm)

6. Distantia cristarum- the distance between the most distant points of the iliac crest. (normally 28-29 cm)

When determining the size of the pelvis, it is necessary to take into account the thickness of its bones, it is judged by the value of the so-called Solovyov index - the circumference of the wrist joint. The average value of the index is 14 cm. If the Solovyov index is greater than 14 cm, it can be assumed that the pelvic bones are massive and the size of the small pelvis is smaller than expected.

Rhombus of Michaelis In a standing position, the so-called lumbosacral rhombus, or the rhombus of Michaelis, is examined. Normally, the vertical size of the rhombus is on average 11 cm, the transverse one is 10 cm. In case of violation of the structure of the small pelvis, the lumbosacral rhombus is not clearly expressed, its shape and dimensions are changed.

The study of the pelvis is important in obstetrics because its structure and size have a decisive influence on the course and outcome of childbirth. A normal pelvis is one of the main conditions for the correct course of childbirth. Deviations in the structure of the pelvis, especially a decrease in its size, complicate the course of childbirth or present insurmountable obstacles for them. The study of the pelvis is carried out by examining, feeling and measuring its size. On examination, attention is paid to the entire pelvic area, but special attention is paid to the lumbosacral rhombus (Mnkhaelis rhombus). lumbar vertebra and the beginning of the middle sacral crest: the lateral angles correspond to the posterior superior iliac spines; lower - the top of the sacrum; above and outside, the rhombus is limited to the protrusions of the large spinal muscles, from below and outside - the protrusions of the gluteal muscles. With a normal pelvis, in well-built women, the rhombus approaches a square and is clearly visible upon examination. With an incorrect physique and shape of the pelvis, the rhombus is not expressed clearly enough and its shape changes. In the study of the large pelvis, the spines and crests of the iliac bones, symphysis and skewers of the femur are palpated.

Pelvis measurement

Of all the methods of examining the pelvis, the most important is its measurement. Rice. 38. Diagonal conjugate measurement. There are buttons at the ends of the tazomer branches; they are applied to the places, the distance between which is to be measured. To measure the transverse size of the outlet of the pelvis, a tazomer with crossed branches was designed. Rice. 36. Measurement of the transverse dimensions of the pelvis. 1- distantia cristarum; 2 - distantia splnarum; 3- distantia trochantcrica. Four sizes of the pelvis are usually measured: three transverse and one straight. The following dimensions are considered transverse. Distantia spinarum - the distance between the non-superior iliac spines. The buttons of the tazomer are pressed against the outer edges of the anterior superior spines. This size is usually 25-26 cm. Distantia cristarum - the distance between the most distant points of the iliac crests. After measuring distantia spinarum, the buttons of the tazomer are moved from the spines along the outer edge of the iliac crest until the greatest distance is determined; this distance will be distantia cristarum; it averages 28-29 cm. Distantia trochanterica - the distance between the large skewers of the femur. They look for the most prominent points of the large skewers and press the buttons of the tazomer to them. This size is 30-31 cm. By the size of the outer dimensions, one can judge with some caution the size of the small pelvis. The ratio between the transverse dimensions is also important. For example, normally the difference between distantia spinarum and distantia cristarum is 3 cm; if the difference is smaller, this indicates a deviation from the norm in the structure of the pelvis.

Conjugata externa - external conjugate, that is, the direct size of the pelvis. The woman is laid on her side, the underlying leg is bent at the hip and knee joints, the overlying one is pulled out. The button of one branch of the tazomer is placed in the middle of the upper outer edge of the symphysis, the other end is pressed against the supra-sacral fossa, which is located between the spinous process of the V lumbar vertebra and the beginning of the middle sacral crest (the supra-sacral fossa coincides with the upper angle of the lumbosacral rhombus). The outer conjugate is normally 20-21 cm (Fig. 37).

Rice. 37. Measurement of the external conjugate (scheme). The upper outer edge of the symphysis is easily determined, to clarify the location of the supracacral fossa, slide your fingers along the spinous processes of the lumbar vertebrae towards the sacrum; the fossa is easily determined by touch under the protrusion of the spinous process of the last lumbar vertebra. In obese women, it is difficult or even impossible to feel the supra-sacral fossa. In such cases, the lateral corners of the lumbosacral rhombus are connected (corresponding to the posterior superior spines) and retreat from the center of this transverse line upwards by two transverse fingers (3-4 cm). This place corresponds to the supra-sacral fossa. The button of the tazomer is installed here. The external conjugate is important, by its size one can judge the size of the true conjugate. To determine the true conjugate, 9 cm is subtracted from the length of the outer conjugate. For example, with an outer conjugate of 20 cm, the true conjugate is 11 cm, with an outer conjugate of 18 cm, the true conjugate is 9 cm, etc. The difference between the outer and true conjugates depends on the thickness of the sacrum, symphysis and soft tissues. The thickness of the bones and soft tissues in women is different, so the difference between the size of the outer and true conjugates does not always correspond exactly to 9 cm. cape sacrum. Diagonal cojugate is determined during a vaginal examination of a woman (Fig. 38), which is performed in compliance with all the rules of asepsis and antisepsis. II and III fingers are inserted into the vagina, IV and V are bent, their rear rests against the perineum. The fingers inserted into the vagina are fixed at the top of the cape, and the edge of the palm rests against the lower edge of the symphysis. After that, the second finger of the other hand marks the place of contact of the examining hand with the lower edge of the symphysis. Without removing the second finger from the marked point, the hand located in the vagina is removed and measured with a pelvis or centimeter tape using another person, the distance from the top of the third finger to the point in contact with the lower edge of the symphysis. The diagonal conjugate with a normal pelvis is an average of 12.5 -13 cm. To determine the true conjugate, 1.5-2 cm is subtracted from the size of the diagonal conjugate. It is not always possible to measure the diagonal conjugate, because with normal pelvis sizes, the cape is not reached or is palpated with difficulty. Rice. 39. Measurement of the exit a-measurement of the direct size of the exit of the pelvis; b - measurement of the transverse size of the outlet of the pelvis. The woman lies on her back, her legs are bent at the hip and knee joints, spread apart and pulled up to her stomach. The direct size of the pelvic outlet is usually measured with a tazometer. One button of the tazomer is pressed to the middle of the lower edge of the symphysis, the other to the top of the coccyx. The resulting size (11 cm) is larger than the true one. To determine the direct size of the outlet of the pelvis, subtract 1.5 cm (taking into account the thickness of the tissues). The transverse dimension of the outlet of the pelvis is measured with a centimeter tape or a pelvis with crossed branches. Feel the inner surfaces of the ischial tuberosities and measure the distance between them. It is necessary to add 1-1.5 cm to the obtained value, taking into account the thickness of the soft tissues located between the buttons of the tazomer and the ischial tubercles. Determining the shape of the pubic angle is of known clinical importance. With normal pelvic dimensions, it is 90-100 °. The shape of the pubic angle is determined by the following method. The woman lies on her back, her legs are bent and pulled up to her stomach. With the palmar side, the thumbs are applied close to the lower branches of the pubic and ischial bones; the touching ends of the fingers are pressed against the lower edge of the symphysis. Rice. 40 Determination of the shape and size of the pubic arch. The oblique dimensions of one side are compared with the corresponding oblique dimensions of the other. With a normal structure of the pelvis, the size of the paired oblique dimensions is the same. A difference greater than 1 cm indicates an asymmetric pelvis. If necessary, to obtain additional data on the size of the pelvis, its compliance with the size of the fetal head, deformities of the bones and joints, X-ray examinations of the pelvis are performed (according to indications). Radiography is carried out in the position on the back and on the side, which makes it possible to judge the shape of the sacrum, pubic and other bones; a special ruler determines the transverse and direct dimensions of the pelvis. The head is also measured and, on this basis, it is judged that its size corresponds to the size of the pelvis. When measuring the pelvis externally, it is difficult to take into account the thickness of its bones. Meanwhile, this is of great importance because the thicker the bones, the smaller the size of the cavity of the small pelvis, even with normal or close to normal sizes of the large pelvis. To judge the thickness of the pelvic bones, measuring the circumference of the wrist joint of a pregnant woman with a centimeter tape (Soloviev index) is of known importance ). The average value of this circumference is 14 cm. If the index is greater, it can be assumed that the pelvic bones are massive and the dimensions of its cavity are smaller than would be expected from the measurements of the large pelvis.

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