Narrow pelvis. complications of childbirth

Narrow pelvis. Complications of childbirth 0 5

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Narrow pelvis. Complications of childbirth

"Narrow pelvis" is a diagnosis that causes a lot of questions. Hearing him, women are going through: how will the childbirth take place and what "pitfalls" are possible at the birth of the baby?

Lyudmila Petrova obstetrician-gynecologist of the highest qualification category, head of the maternity department of the maternity hospital № 16, St. Petersburg

During the expulsion of the fetus from the uterine cavity during childbirth, it passes through the bone base of the birth canal-a small pelvis, an almost stubborn, solid bone ring. Deviations in the structure of the bone pelvis, especially a decrease in its size, can complicate the course of labor and even present an insurmountable obstacle to passage through it the head of the fruit.

The pelvis is considered an anatomically narrow pelvis, in which all or at least one of the main dimensions is shortened in comparison with normal ones by 1.5-2 cm or more. Narrowing of the pelvis may also be accompanied by deformation of the pelvic bones.

There is still an understanding of the functional usefulness of the pelvis. In women with small pelvic spontaneous spontaneous deliveries without any complications are observed when there is no discrepancy between the size of the fetal head and the pelvic size, which happens with a small fetal head, its good capacity for configuration (the head decreases due to the fact that the unbroken bones skulls are found one on top of another like tiles) and satisfactory labor. Such an anatomically narrow pelvis is considered functionally complete.

A clinically narrow pelvis is a pelvis that presents a difficulty or an obstacle to the course of a specific birth, regardless of its size. This discrepancy (disproportion) between the head of the fetus and the mother's pelvis. It can be observed with absolutely normal pelvic size and large fetal head size, its reduced ability to configure, if it is inserted incorrectly and other reasons. Thus, it should be borne in mind that not every anatomically narrow pelvis will be both narrow and functional, while not every functionally narrow pelvis is anatomically narrow. The incidence of a clinically narrow pelvis with an anatomically narrow pelvis is 25-30%, and at a normal pelvic size 0.3%.

Causes of an anatomically narrow pelvis

The formation of the female pelvis is influenced by many factors:

frequent, including infectious, diseases in childhood, malnutrition, lack of vitamins, metabolic disorders, pelvic deformities lead to damage to the bones and joints of the pelvis in rickets, tuberculosis, poliomyelitis, tumors, with incorrect fracture fusion, congenital abnormalities of the pelvis;

deformation of the spine (with its curvature), absence or shortening of the limb, pathology in the hip joints;

hormonal disorders during puberty (this reason is one of the main).


With a narrow pelvis due to the high-frontal head, the uterus rises very high and begins to deviate from the vertical almost to the horizontal position. In primiparas, due to the elastic wall of the abdomen, a so-called "pointed" abdomen is observed. In re-birth due to the weakness of the abdominal press, the uterus deviates even more anteriorly, characterized by a "pendulous" abdomen.

Important information about the structure of the pelvis is obtained by its instrumental measurement. The obstetrician is mainly interested in the structure and dimensions of the small pelvis (the internal bone channel created by the pelvic bones), which is crucial when passing through the fetus, especially its head. The internal dimensions of the small pelvis are indirectly judged by external measurement of the pelvis, which is carried out by traditional methods - with the help of a tasometer (obstetric circular) and a centimeter tape. Based on the obtained data, one can judge the anatomical features of the small pelvis, between the sizes of the big and small pelvis there is a dependence.

Only after a vaginal examination in which one of the pelvic dimensions is determined, the pelvic wall is inspected from the inside, its capacity, the presence of deformities, taking into account the data of external tubal measurement, it is possible to diagnose the narrow pelvis and the degree of its narrowing.

However, the final diagnosis of the anatomically narrow pelvis, its shape and degree of narrowing is established using additional methods of investigation: the X-ray method (X-ray) and the computer tomography pelvimetry method, which is more accurate and safer than the X-ray method, and ultrasound. These methods of research are used if, as a result of external measurements of the pelvis, there is a suspicion of its significant narrowing.

With an anatomically narrow pelvis, delivery can be carried out through the natural birth canal and in an operative way. Births can:

a) flow normally;

b) be difficult, but to end safely when providing the right help;

c) be very severe, with complications that are dangerous for the mother and the fetus.

There are four degrees of narrowing of the anatomically narrow pelvis.

When III-IV grades narrowing of the small pelvis, it is considered absolutely narrow and is an indication for delivery only by cesarean section, as well as in the presence of bone tumors, gross deformations in the small pelvis, which represent an obstacle to the passage of the fetus.

When II degrees narrowing of the pelvis due to possible dangerous complications for the mother and the fetus most often resort to delivery by caesarean section. It is possible to lead births through the natural birth canals with premature pregnancy (in this case, the fetal size is small, so that delivery is possible even through a narrow pelvis).

The above situations are extremely rare.

When And degrees narrowing of the small pelvis, births usually begin to lead through the natural birth canal with the definition of functional fullness of the pelvis. Caesarean section is performed with a combination of narrowing with pelvic presentation (in this case the fetus is turned by the pelvic end to the exit from the uterus), a large, especially born, fetus, an incorrect position of the fetus, a scar on the uterus, when combined with other aggravating moments.

Features of childbirth

In most cases, births with an anatomically narrow pelvis with average head size, good ability to configure with vigorous labor are normal. However, there are some complications that are typical for labor with a narrow pelvis:

  • Most often occurs untimely outpouring of amniotic fluid (преждевременное или раннее). В связи с узостью таза головка не вставляется в таз, а стоит высоко и подвижна над входом в малый таз, не происходит разделение вод на передние и задние - в норме их разделяет головка, прижавшаяся к костям таза, давление на плодный пузырь возрастает, он вскрывается. С током вод могут выпасть петли пуповины или конечности плода (ручка или ножка). Если мелкую часть плода не удается заправить за головку, то уменьшается объем узкого таза и создается дополнительное препятствие для изгнания плода. Выпавшая петля пуповины может прижаться головкой к стенке таза и привести к гибели плода от гипоксии (кислородной недостаточности). When выпадении пуповины роды заканчивают путем операции кесарева сечения.
  • Excessive mobility of the uterus, a high-standing head predispose to wrong position of the fetus (lateral, oblique, pelvic presentation), incorrect insertion of the head (lateral), its extension with the formation of extensor presentations of the fetus (normally the head is bent during childbirth, the nape is born first, with the extensions the head is unbent, the forehead or face is required).
  • Occurs primary or secondary weakness of labor, which is facilitated by a non-timely discharge of amniotic fluid, a prolonged high position of the head, which unnecessarily stretches the lower segment of the uterus, slows the opening of the cervix, tightens the delivery, leads to fatigue in the parturient woman. In primiparas, the primary weakness of labor is more often, due to the need to overcome the narrowed pelvis for a long time, and for the uterus having a malfunction with overstretch, its changes in previous births or abortions.
  • A prolonged period of labor, a prolonged anhydrous period, may result to infection of the mother and fetus due to the penetration of pathogenic microflora from the vagina and uterus.
  • Developing intrauterine fetal hypoxia. During fights or attempts, the fetus's head undergoes a strong configuration (its volume decreases due to the fact that the head bones overlap one another in the places of the seams and fontanelles, which leads to the excitation of the centers of the nervous regulation of the fetal heart, causing a decrease in the heart rhythm of the fetus, exceeding in its duration of uterine contraction, and thus becomes the cause of hypoxia.Often, hypoxia of the fetus is aggravated by a violation of uteroplacental blood circulation caused by abnormalities of the contractile activity of the uterus (turbulent odovoy activity, weakness). Therefore, therapeutic measures are short-lived and ineffective.
  • The course of labor is different longer than usual.
  • Occurs compression of soft tissues of the birth canal between the pelvic bones and the fetal headcaused by prolonged standing of the head in one plane of the pelvis. In addition to the cervix and vagina, the bladder and rectum are squeezed, which is accompanied by a violation of blood circulation in them and swelling of the cervix, vagina, bladder, external genitalia.
  • A sharp difficulty in the passage of the head for a long time in the same plane of the pelvis causes painful, intense, sometimes convulsive labor, which can lead to overgrowth of the lower segment of the uterus, which is a symptom of a threatening uterine rupture
  • When некоторых видах узкого таза головка плода отклоняется в сторону промежности в боль шей степени, чем при нормальном тазе, ткани промежности сильно растягиваются, и, если не рассечь промежность, происходит ее deep rupture.
  • The prolonged course of labor, fatigue of the parturient woman with a prolonged anhydrous interval may cause bleeding in the postpartum and early postpartum period because of a bad uterine contraction. This complication requires an operation of manual entry into the uterine cavity.
  • Most often arise complications threatening the fetus. Hypoxia in childbirth can lead to the birth of a child in a state of asphyxia, a violation of cerebral circulation, there are craniocerebral injuries of varying severity, which subsequently requires observation by a neuropathologist and rehabilitation measures.

On what grounds are the narrow pelvis judged?

To make the assumption about anatomical changes of a bone basin to the doctor allow following signs:

  • low height of the pregnant (less than 160cm);
  • short fingers and toes (shoe size is less than 23 (36), brush length is less than 16 cm, I and III fingers are less than 6 and 8 cm, respectively);
  • a woman's height of more than 165 cm in combination with lameness, gait disturbance, curvature of limbs, spine;
  • the identification of all factors in the life of a woman who could have an adverse effect on the formation of the female pelvis;
  • violation of the menstrual cycle;
  • an indication of the complicated course of previous births.

Actions of doctors

Keeping the birth in a narrow pelvis requires a doctor-obstetrician of great excerpt and art. Only during labor (at the end of the first and second period) is the question resolved whether this anatomically narrow pelvis is functionally narrow or normal. Functional evaluation of the pelvis is preceded by anatomical evaluation (determination of pelvic shape and degree of narrowing) and determination of the size of the fetus.

Whenчинами клинически узкого таза помимо его анатомического сужения могут быть: крупный плод, гидроцефалия (водянка мозга с большими размерами головки плода), неправильное вставление головки, перенашивание.

About the clinically narrow pelvis is said, when the full opening of the cervix, the fetal head does not move along the birth canal. 

The conditional waiting time for lowering the head in primiparous women is 1-1.5 hours, in the case of re-occurring ones, up to 1 hour, although this primarily depends on the condition of the mother and the fetus.

When наличии клинически узкого таза отказываются от выжидательной тактики ведения родов и в интересах плода и матери склоняются в сторону операции кесарева сечения. When некоторых патологических неправильных вставлениях головки функциональную оценку таза вообще не проводят, т.к. роды через естественные родовые пути невозможны.

It is important to maintain the integrity of the fetal bladder for the longest time possible, for this the woman in labor follows the bed rest, is placed on the side where the deflected head is located, or where the frontal back is facing, which helps to lower the occiput and preserve amniotic fluid.

Childbirth is conducted under constant careful supervision of the fetus and contractile activity of the uterus with the help of cardiotocographs. Regularly used medicines that improve utero-placental circulation.

С целью профилактики слабости родовой деятельности широко применяют витамины, глюкозу для увеличения энергетического потенциала, обезболивающие и спазмолитические средства. When развитии слабости родовой деятельности родоусиление применяют редко - при легких степенях относительного клинического несоответствия.

Проводится тщательное наблюдение за состоянием роженицы, выделениями из половых путей, за мочеиспусканием. When затруднении мочеиспускания мочу выводят катетером.

More often than usual, vaginal examinations are carried out: they are mandatory after the outflow of water for the purpose of timely diagnosis of the prolapse of the umbilical cord or small part of the fetus; they are needed for functional evaluation of the pelvis (insertion of the head, its configuration, progression through the birth canal).

During labor in women with a narrow pelvis, the perineal incision is widely used.

At the time of the birth of the head or immediately after the birth of the baby, the uterine contracting agents are introduced to prevent bleeding. Pregnant women with an anatomically narrow pelvis belong to a high risk group due to possible complications for the mother and fetus. Timely prenatal hospitalization allows you to prevent re-admission, to conduct a follow-up examination in order to clarify the shape and degree of narrowing of the pelvis, to develop the optimal tactics of labor management.