Extension inserts. Extensor insertions of the fetal head

AND WRONG

POSITIONS OF THE FETAL

Childbirth with an incorrect presentation of the head and incorrect positions of the fetus includes childbirth with an extensor presentation of the head, its asynclitic insertions, childbirth with a high straight and low transverse position of the sagittal suture, childbirth with oblique and transverse positions of the fetus. The listed situations should be considered pathological, since in some of them spontaneous birth is impossible (anterior type of facial pre-fetus, frontal presentation of a full-term fetus, transverse position), and in others the risk of an unfavorable outcome for the mother and fetus increases significantly (maternal and child injuries , hypoxia of the fetus and newborn).

The causes of malpresentation of the head and incorrect positions of the fetus are numerous. This pathology is caused by a change in the shape of the uterus (saddle-shaped, bicornuate, with a septum in the body, the presence of fibroids, etc.), flabbiness of its lower segment, various forms of narrowing of the pelvis that make it difficult to correctly insert the head, features of the shape of the head, impaired tone of the fetal muscles, the presence of a neck tumor, etc.

Considering the rather great danger for the mother and fetus in case of incorrect positions and breech presentation, in modern obstetrics there is a clear tendency to expand the indications for cesarean section. Correcting the position of the fetus and changing the presentation to more favorable manual techniques (rotation of the fetus, extension of the head during frontal presentation with a finger inserted into the fetal mouth, etc.) is currently not necessary.

Childbirth at extensor breech heads

What applies To childbirth at extensor breech heads?

Childbirth with an extension presentation of the head includes such pathological obstetric situations in which the presenting head in the first stage of labor is firmly established in one degree or another of extension. During physiological childbirth, flexion of the head occurs at this moment. This extension, in turn, leads to changes in the biomechanism of labor.

On which degrees extension divide such pathological

presentation heads?

Such pathological presentations, according to the degree of extension of the head, are divided into the first degree, which is called anterior cephalic presentation, the second degree - frontal presentation and the third degree - facial presentation (Fig. 16.1).

Why does childbirth with an extension presentation most often occur with the formation of a posterior view?

Rice. 16.1. Three degrees of head extension: a - anterocephalic; b - frontal; V- facial

Rice. 16.2. Mechanism

rear view formations

when the head is extended

When the fetal head extends, its most voluminous part becomes the occipital part, which turns into the sacral cavity, to the side where there is more free space (Fig. 16.2).

It is advisable to consider the features of the biomechanism of labor separately for each of the three degrees of extension.

Childbirth at

anterior-head presentation -

first degree extension

heads

How put diagnosis anteriorly-

th presentation?

The diagnosis is made by vaginal

research: the large fontanel is determined below the small one, along the wire axis of the pelvis. Diagnosis is also helped by having a rear view.

What is happening V first moment biomechanism childbirth?

At the first moment of the biomechanism of the horns, extension of the head occurs. In this case, the head is inserted at the entrance to the small pelvis with its direct size equal to 12 cm.

How is different first moment biomechanism childbirth at anterior-head presentation from physiological childbirth?

With an anterior cephalic presentation, at the first moment of the biomechanism of labor, the fetal head is inserted into the entrance to the small pelvis not in a bent state, as during physiological childbirth, but in a slightly straightened state. Insertion of the head in this presentation occurs not in a small oblique size (9.5 cm), as in the occipital presentation, but straight (12 cm) (Fig. 16.3).

What is yourself second moment biomechanism childbirth?

The second point of the biomechanism of childbirth is the internal “wrong” rotation of the head (with the back of the head) and the forward movement of the head along the birth canal (Fig. 16.4).

Rice. 16.3 The mechanism of labor during

anterior cephalic presentation.

Rice. 16.4. Biomechanism childbirth at

anterior-head presentation.

IImoment

Which movement sovrshevt head V third moment biomechanism childbirth ? At the third moment of the biomechanism of childbirth, the head is fixed at the lower edge of the symphysis pubis by the region of the glabella (glabella) and bends. At when the head is flexed, the crown and occiput erupt (Fig. 16.5).

What such fourth moment biomechanism childbirth? . The fourth moment of the biomechanism of childbirth begins after fixation of the suboccipital fossa at the apex of the coccyx and represents the extension of the head. At in this case, the head is completely born from the genital tract (Fig. 16.6).

What is leading dot And what size eruption occurs heads?

The leading point is the large fontanel. Cutting through the cooking occurs with a direct size (diameter frontooccipitalis) equal to 12 cm, and a corresponding circumference equal to 35 cm.

What are peculiarities clinics childbirth at anterior-head presentation ?

The main difference between the birth clinic with anterior cephalic presentation is the long duration of the second period, which can lead to weakness of labor and fetal suffering (hypoxia).

Rice. 16.5. Biomechanism of childbirth

anterior cephalic presentation.

Ill moment

Rice. 16.6. Biomechanism of childbirth

anterior cephalic presentation.

What forecast outcome childbirth For mothers And fetus at anterior-head presentation?

Spontaneous birth is possible, but perinatal mortality is significantly higher than with physiological birth; Frequent complications include asphyxia and fetal traumatic brain injury.

Maternal traumatism is also significantly higher (cervical and perineal ruptures).

What plan conducting childbirth should stick to at ne-

redgoloYonom presentation?

In modern conditions, anterior cephalic presentation should be considered a relative indication for cesarean section. In the absence of deviations from the normal course, childbirth can be completed through natural means. The operation of applying obstetric forceps can only be performed by an experienced obstetrician.

Childbirth at frontal presentation - second degree extension heads

What called frontal presentation?

Frontal presentation is the extension variant

corporal presentation of the head, in which the leading point is located in the frontal region of the head.

How diagnose frontal presentation?

The diagnosis of frontal presentation is made during childbirth when, during vaginal examination, the forehead is lower than other parts of the head. At the same time, following the frontal suture with your finger, on the one hand you can determine the root of the nose and orbit, on the other - the anterior edge of the large fontanelle.

Possible whether childbirth at frontal presentation through

natural generic ways?

Childbirth with frontal presentation through the natural birth canal is impossible, since the insertion of the head occurs with a large oblique size (mentoccipitalis) equal to 13.5 cm, which does not correspond to the size of the small pelvis (the largest size of the small pelvis is 1 3 cm - this is the transverse size of the entrance to the small pelvis, all other sizes are smaller). Therefore, frontal presentation of the fetus is an absolute indication for cesarean section.

What forecast outcome childbirth For mothers And fetus at frontal

presentation?

Spontaneous birth with frontal presentation can only occur in the presence of a premature fetus or with a very large pelvis.

What plan conducting childbirth should stick to at establishing diagnosis frontal presentation?

Considering the great danger for the woman in labor (threat of uterine rupture, formation of fistulas during prolonged standing of the head in the pelvic cavity) and the fetus (asphyxia, traumatic brain injury), frontal presentation with a living fetus should be considered an absolute indication for cesarean section. An operation to correct the position of the head in the facial or occipital position by extending or bending it with a finger inserted into the mouth can cause injury to the fetus and rarely leads to success, since the cause of extension is not eliminated.

In case of intrauterine death of the fetus, a fetal-destroying operation is performed - craniotomy.

Childbirth at facial presentation - thirddegree extension heads

What called facial presentation?

Facial presentation is a head presentation with the head maximally extended. The leading point in this case becomes the fetal chin.

Possible whether childbirth at facial presentation?

Childbirth with a facial presentation is possible only in the posterior view. The appearance of the fetus is determined by the back of the head: posterior view - the back of the head faces the sacrum.

How put diagnosis facial presentation?

Extension of the head can sometimes be recognized during external examination, while the chin is identified above the entrance to the small pelvis on one side, and the occiput of the fetus on the other; The cervical curvature is sharply expressed. A vaginal examination finally confirms the diagnosis: a heterogeneous, soft (due to edema) presenting part is determined. The nose, eye sockets, cheek bones, mouth, and chin of the fetus are palpated.

What such first moment biomechanism childbirth at facial

presentation?

The first moment of the biomechanism of childbirth is maximum extension of the head. In this case, the facial line (linea facialis), running from the bridge of the nose to the chin along the back of the nose through the mouth, is located in the transverse dimension of the pelvis (much less often - in the oblique dimension) (Fig. 16.7).

What is happening in second moment biomechanism childbirth?

At the second moment of the biomechanism of childbirth, the head makes an internal “wrong” turn. Rotation occurs during the transition from the wide to the narrow part of the pelvic cavity.

Which movement commits head V third moment biomechanism childbirth?

At the third moment of the biomechanism of childbirth, the head is fixed by the hyoid bone at the lower edge of the pubic symphysis and, bending, is born from the genital tract. In this case, the chin, mouth, nose, eyes, forehead, crown and back of the head appear (Fig. 16.8).

Rice. 16.7. Biomechanism of childbirth

facial presentation.

Rice. 16.8. Biomechanism of childbirth

facial presentation.

Ill moment

What such fourth moment biomechanism childbirth? The fourth moment - internal rotation of the shoulders and external rotation of the head - proceeds in the same way as with any cephalic presentation.

Where located presenter dot V childbirth at facial presentation And what size is happening teething heads?

The leading point is located in the chin area. The eruption of the head occurs with a vertical size (diameter hyobregmaticus) of 9.5 cm and a corresponding circumference of 32 cm.

What are peculiarities clinics childbirth at facial presentation?

Possible complications during childbirth with facial presentation include premature rupture of water, prolapse of the umbilical cord loop, weakness of labor and associated fetal asphyxia.

What forecast outcome childbirth For mothers And fetus at facial presentation?

Childbirth in the posterior form of facial presentation can end spontaneously, but the incidence of asphyxia and birth trauma (compression of the neurovascular bundles of the neck) in children is higher than during physiological childbirth.

Birth trauma is more common in mothers -

crotch tear. Due to premature rupture of amniotic fluid, postpartum infectious diseases are more common.

Why impossible childbirth V front form facial presentation?

Childbirth in the anterior form of facial presentation is impossible due to the impact of the hanger into the pelvic cavity. The shoulder girdle and head, being at the same level, cannot simultaneously pass through the pelvic inlet (Fig. 16.9). Therefore, the anterior view of facial presentation is an absolute indication for cesarean section.

Which tactics conducting childbirth should stick to at

rear form facial presentation?

Facial presentation, given the higher percentage of complications for the mother and fetus than during physiological labor, should be considered a relative indication for cesarean section.

In multiparous women with posterior facial presentation of the second fetus in multiple pregnancies, with a premature fetus, as well as in the presence of a capacious pelvis and the absence of other complications (weakness of labor, premature rupture of water), childbirth can be carried out through the natural birth canal.

Rice. 16.9. Anterior view of facial presentation

Childbirth at asynclitic insertions heads

What called asynclitism?

Asynclitism is an abnormal position of the head in the inlet or in the pelvic cavity, in which the sagittal suture deviates anteriorly or posteriorly (towards the womb or sacrum). In this case, one of the parietal bones is lower than the other.

Which exist kinds asynclitism?

There are two main types of asynclitism: anterior, in which the anterior parietal bone of the head, facing the womb, descends first, the sagittal suture is deflected posteriorly (Nägele asynclitism), and posterior, in which the posterior parietal bone (facing the sacrum) descends first, the sagittal suture is deflected anteriorly (Litzmann asynclitism) (Fig. 16.10).

Rice. 16.10. Off-axis head insertion options:

1 - anterior asynclitism (Nägele asynclitism);

2 - posterior asynclitism (Litzmann asynclitism)

Recently, an increase in the frequency of transversely contracted pelvis has been noted, which is characterized by an oblique asynclitic insertion of a sagittal suture in the plane of the entrance to the small pelvis, when the sagittal suture is located in one of the oblique dimensions of the entrance, and the anterior or posterior parietal bone descends first.

What are causes education asynclitism?

A slight asynclitism is physiological and is apparently associated with the existing pelvic tilt.

The main reasons for the formation of pronounced, pathological asynclitism: weakness of the anterior abdominal wall, in which the longitudinal axis of the uterus and fetus deviates anteriorly; relaxation of the lower segment of the uterus, narrowing

pelvis (especially flat forms).

How put diagnosis asynclitic insertions heads?

The diagnosis is made during a vaginal examination in the second stage of labor by the deviation of the sagittal suture from the pelvic axis.

What are peculiarities biomechanism childbirth at asynclitic-

to their insertions heads?

The peculiarities of the biomechanism of childbirth are that first one parietal bone descends into the pelvic cavity (the anterior one - with anterior asynclitism, the posterior one - with posterior asynclitism), then the other. In some cases (for example, with a planar-rachitic pelvis), asynclitism is a useful adaptive mechanism that allows the head to pass through the reduced direct size of the entry plane.

What forecast at asynclitic insertions heads?

With moderate asynclitism, labor can end spontaneously.

Severe asynclitism, especially posterior, is a serious pathology for both the fetus (asphyxia) and the mother (infection due to prolonged labor, risk of uterine rupture and the formation of bedsores during prolonged standing of the head).

What is tactics doctor at establishing diagnosis asynclitic insertions heads?

With moderate asynclitism, childbirth can be managed expectantly, with a functional assessment of the pelvis and strict monitoring of the dynamics of labor; the head should not be allowed to stand in one plane for a long time (more than 1 hour) and other signs of a clinically narrow pelvis should not appear.

In this case, childbirth should be completed by cesarean section. If the fetus is dead, then in the interests of the health and life of the mother (risk of uterine rupture, fistula formation), a craniotomy should be performed.

When a pronounced asynclitism is detected, especially posterior asynclitism, a cesarean section should be performed immediately in the interests of the mother and fetus.

Which pathological state include To anomalies standing

sagittal seam ?

These pathological conditions include high straight and low transverse position of the sagittal suture.

Why high direct And low transverse standing sagittal seam (heads) should count pathology? These situations should be considered pathological, because due to unfavorable ratios of the sizes of the head and pelvis, the advancement of the fetus through the birth canal in most cases becomes impossible without the use of certain obstetric operations.

Childbirth at high direct And low transverse standing sagittal seam

What such high direct standing sagittal seam?

The high straight position of the sagittal suture is a position in which the head is at the entrance to the small pelvis with a sagittal suture in straight size (Fig. 16.11).

What are causes high direct standing sagittal

seam?

Rice. 16.11. High straight position of the head: a - anterior view; b - rear view

The main causes of this pathology are changes in the shape of the pelvis (especially a transversely narrowed pelvis) and the head (severe brachycephaly).

What is tactics doctor at establishing diagnosis high

direct standing sagittal seam?

In some cases, spontaneous birth is possible, which occurs without the head making an internal rotation. This is observed if the transverse size of the pelvis is narrowed, the direct dimensions remain normal or increased, and the head is turned anteriorly with the occiput (anterior view). Therefore, in this clinical situation, the pelvis should be carefully measured and, if possible, the true conjugate should be accurately determined.

If the direct dimensions of the pelvis are narrowed or the sagittal suture is high and straight in the posterior view, the issue should be resolved in favor of a cesarean section due to the risk of uterine rupture and intrauterine fetal death.

Some obstetricians propose a technique that corrects the position of the head (the “Kegel ball” method): the head is pushed away from the entrance to the pelvis by the hand inserted into the vagina and rotates around the longitudinal axis. This technique is rarely successful and can cause serious injury to the fetus, so it is not used.

What such low transverse standing sagittal seam?

Low transverse position of the sagittal suture is a position in which the sagittal suture is located in the transverse dimension of the pelvic outlet (Fig. 16.12).

What are causes emergence given pathology?

Narrowing of the pelvis (especially flat pelvis), small head size and decreased tone of the pelvic floor muscles.

What is tactics doctor at

establishing diagnosis

low transverse standing sagittal seam?

In some cases it is possible

Rice. 16.12. Low transverse position of the head

spontaneous birth. If the head remains in the exit plane for a long time (up to 1 hour) and if there are indications from the fetus (asphyxia), the birth should be completed using obstetric forceps. However, the function of the forceps here is atypical - not only attraction, but also rotation of the head, therefore such an operation should be performed by an experienced obstetrician and preferably with straight (Russian) forceps without pelvic curvature. The application of forceps in such an obstetric situation is extremely traumatic for both the fetus and the mother.

Childbirth at incorrect provisions fetus

What called wrong position fetus?

Abnormal fetal position is a clinical situation in which the axis of the fetus intersects with the axis of the uterus.

Which there are incorrect provisions fetus? Incorrect fetal positions include transverse and oblique positions.

What called transverse position fetus?

Transverse position (situs transversus) is a clinical situation in which the axis of the fetus intersects the axis of the uterus at a right angle, and large parts of the fetus are located above the crests of the iliac bones (Fig. 16.13).

What called oblique position fetus?

Oblique position (situs obliquus) is a clinical situation in which the axis of the fetus intersects the axis of the uterus at an acute angle, and the underlying large part of the fetus is located in one of the iliac cavities of the large pelvis (Fig. 16.14). The oblique position is essentially a transitional state: during childbirth it turns into either longitudinal or transverse.

How determine position And view positions fetus at transverse position fetus?

The position of the fetus in the transverse position is determined by the position of the head: if the head is on the left - the first position, if the head is on the right - the second position.

The type of position in the transverse position is determined by

back: if it is facing anteriorly - anterior view, if backward - posterior view.

What is etiology transverse provisions fetus?

In the etiology of the transverse position of the fetus,

Rice. 16.13. Transverse position of the fetus. First position, front view

Rice. 16.14. Oblique position of the fetus. First position, front view

the following factors: spatial discrepancy between the uterine cavity and the fetus as a result of multiple pregnancy, prematurity, polyhydramnios; malformations of the uterus, narrow pelvis, abnormalities in the location of the placenta, fetal malformations, short umbilical cord.

On basis what data Can put diagnosis transverse or oblique provisions fetus?

Recognition of the transverse or oblique position of the fetus is quite possible on the basis of external examination alone. With a transverse position of the fetus, the uterus has a transverse oval shape, the fundus of the uterus usually stands much lower than with a longitudinal position, and the presenting part is absent. With an oblique position of the fetus, the uterus has an oblique oval shape. The head or buttocks are located in one of the iliac regions, below the level of the iliac crest. The diagnosis is clarified by vaginal examination, when the presenting part is not palpable. The final diagnosis is made by ultrasound examination.

Which complications observed V childbirth at transverse position fetus?

The first possible complication is early discharge of water, which occurs because with the transverse position of the fetus there is no distinction between the anterior and posterior waters and the intrauterine pressure is concentrated at the lower pole of the membranes.

Early rupture of water entails other serious complications: loss of small parts of the fetus (arms, umbilical cord), conditions are created for the development of chorioamnionitis during childbirth, and an advanced transverse position of the fetus is formed. What called running transverse position fetus?

The advanced transverse position of the fetus is the transverse position when the waters have broken, when the fetus in the uterus is completely motionless. Correcting such a transverse position to a longitudinal one by turning is completely impossible. In this case, the fetal shoulder is usually driven into the small pelvis, and the handle often falls out (Fig. 16.15).

How dangerous neglected transverse position For fetus and mothers?

In this situation, the fetus often dies or is in a state of hypoxia.

If the transverse position is neglected and labor continues, uterine rupture may occur.

What need to do V given situations?

If there is a threatening uterine rupture, anesthesia must be immediately given to stop labor. If the fetus is alive and there are no symptoms of chorioamnionitis, a cesarean section should be performed. The dead fetus is removed after decapitation.

What is tactics doctor at establishing diagnosis transverse or oblique provisions fetus at pregnant? Every pregnant woman who has a transverse or oblique position of the fetus 3-4 weeks before birth should be hospitalized in the department of pathology of pregnant women. What plan conducting childbirth should stick to? In pregnant women and women in labor with a transverse position of the

Rice. 16.15. Advanced transverse position of the fetus.

Handle falling out. Overdistension of the lower segment of the uterus

Yes, a caesarean section should be performed. The operation can also be performed routinely during a full-term pregnancy.

The operation of turning the fetus onto its leg is very traumatic for the fetus and in a transverse position it is used only in cases of a very premature fetus or incorrect position of the second fetus in case of twins (after the birth of the first fetus).

If there is an oblique position of the fetus, the woman in labor is placed on her side, corresponding to the location of the large part in the iliac region. When the pelvic end of the fetus descends, the latter often takes a longitudinal position. If lying on the side fails to correct the oblique position of the fetus, the issue should be resolved in favor of a cesarean section.

An operation to correct the transverse position of the fetus using external techniques (external rotation onto the head) previously

was widely produced at 35-36 weeks of pregnancy, but is now rarely used. The effectiveness of such an operation is low. The fetus most often again takes a transverse position, since the cause of this pathology is not eliminated by turning. In some cases, the rotation operation leads to severe complications (placental abruption, uterine rupture, fetal asphyxia), which is also the reason for abandoning it.

A pregnant woman with a breech presentation of the fetus is hospitalized in an obstetric hospital at 38-39 weeks for a full examination, determination of the due date, selection of the optimal method of delivery and preparation for childbirth.

As part of the examination of pregnant women in the hospital, the following activities are carried out.

▲ The patient’s medical history, previous somatic and gynecological diseases are studied, and the number and nature of previous pregnancies and births are determined.

▲ Assess the general condition of the pregnant woman, her psychosomatic status, the nature of concomitant extragenital and gynecological diseases, and obstetric complications.

▲ The gestational age is determined based on medical history and ultrasound.

▲ External and internal obstetric examination is carried out to establish the type of breech presentation of the fetus, position and type, identify the degree of “maturity” of the cervix for childbirth, and determine the integrity of the amniotic sac.

▲ Determine the size and shape, the degree of narrowing of the pelvis based on its measurements according to the generally accepted scheme, as well as depending on the size of the lumbosacral rhombus and the height of the pelvis. X-ray pelviometry is used as an objective research method for this purpose.

▲ Using ultrasound, the condition of the fetus and fetoplacental complex is assessed. Based on the data of echographic fetometry, the estimated weight of the fetus is calculated, taking into account that with a weight of more than 3500 g, the fetus is considered large in a breech presentation. Using echography, the functional state of the fetus is studied (based on an assessment of its motor activity, respiratory movements and tone). Echography also makes it possible to identify abnormalities in fetal development, assess the amount of amniotic fluid, and identify tumor-like formations of the uterus and uterine appendages. An important place in diagnosis is occupied by placentography (location of the placenta, structure of the placenta, correspondence of the degree of maturity of the placenta to the gestational age, thickness of the placenta). With the help of Doppler, not only the nature of the uteroplacental, fetal-placental and fetal blood flow is clarified. This technique, in combination with color Doppler mapping, makes it possible to identify umbilical cord pathology and suspect umbilical cord entanglement around various parts of the fetal body.

It is important to establish the type of breech presentation of the fetus, as well as the degree of extension of the fetal head (Fig. 21.3). At I degree of extension (the head is slightly extended) the angle between the spine and the occipital bone of the fetus is 100-110°; at II degree of extension (head moderately extended) - angle 90-100°; at III degree of extension (excessive extension) - angle less than 90°. It is very important to recognize the extensor type of position of the fetal head and arms in a timely manner, since this can lead to their tilting back during the period of expulsion. It is also advisable to determine the sex of the fetus. Male fetuses tolerate the stress of childbirth much less well. More accurate information can be obtained using three-dimensional echography or MRI.

CTG is used to determine the reactivity of the fetal cardiovascular system. The computer CIG method makes it possible to assess the adaptive and compensatory capabilities of the fetus and its anti-stress potential.

An important point in the management of pregnant women with breech presentation is the prevention of post-term pregnancy, which is accompanied by a violation of the morphofunctional state of the fetoplacental complex. There is a violation of the basic functions of the placenta, which causes the “immaturity” of the cervix for childbirth and increases the risk of developing abnormalities in labor. Hypoxia symptoms increase in a post-term fetus. The fetal head loses the ability to shape due to the density of the skull bones, the narrowness of the sutures and fontanelles. The risk of fetal brain injury increases.

Rice. 21.3. Types of extension of the fetal head during breech presentation.

a - the head is bent, the angle is greater than 110°; 6 - 1 degree of extension (the head is slightly extended), the angle between the spine and the occipital bone of the fetus is 100-110°; V - II degree of extension (head moderately extended) - angle 90-100°; I - III degree of extension (excessive extension of the head) - angle less than 90°.

Timely diagnosis and appropriate treatment of gestosis and FPN are necessary. In these cases, the adaptive and compensatory capabilities of the fetus are reduced, which tolerates birth stress much worse.

21.6.1. Choosing a method of delivery for breech presentation of the fetus

After the examination, the issue of choosing a method of delivery is decided individually, which depends on:

· patient's age;

· anamnesis data;

· gestational age;

· concomitant diseases and obstetric complications;

· the body's readiness for childbirth;

· pelvic size;

· condition of the fetus, its weight and sex;

· types of breech presentation;

· degree of fetal head extension.

21.6.1.1. C-section

The choice in favor of abdominal delivery requires a very careful approach, since expanding the indications for caesarean section for breech presentations does not yet guarantee an improvement in perinatal outcomes. During the operation, the fetus may receive a birth injury, since when extracting it, techniques are used that are similar to the extraction of the fetus by the pelvic end, which is used when conducting childbirth through the natural birth canal. To a large extentdegree, the risk of fetal injury during cesarean section increases with a premature or large fetus, an extended position of its head, untimely release of amniotic fluid, and insufficient surgical access. In addition, the risk of maternal morbidity and mortality after surgery also increases.

The optimal rate of cesarean section, which is directly related to a decrease in perinatal mortality, is 60-70%. It should be emphasized that in the vast majority of cases, breech presentation itself is not an indication for cesarean section. However, quite often there is a combination with various complicating factors. Taking into account that childbirth with breech presentation is classified as pathological, in these situations its course and outcome are significantly complicated, which forces the issue to be resolved in favor of a cesarean section.

Abdominal delivery in a planned manner with breech presentation, even without associated complications, is indicated for:

· foot presentation of the fetus;

· posterior view of breech presentation;

· extension position of the fetal head.

Danger breech presentation lies in the fact that after the discharge of amniotic fluid, the legs, and then the buttocks and torso of the fetus begin to quickly move forward along the birth canal when the cervix is ​​not yet sufficiently smoothed and dilated. In this case, the fetal head, as a denser and larger part, is not able to pass through an insufficiently opened or spasmodic cervical pharynx, which leads to asphyxia and injury to the fetus or its death. In addition, when attempting to remove a retained head, rupture of the cervix or lower segment may occur.

During childbirth the initial extension of the head further aggravated, the biomechanism of labor is disrupted, which leads to injury to the fetus (damage to the cervical spine, rupture of the tentorium cerebellum, cerebral hemorrhages, formation of subdural hematomas).

In the posterior form of breech presentation the biomechanism of birth is also disrupted, since the bridge of the nose rests against the pubic symphysis (with the head bent), and when the head is extended above the symphysis, the chin is delayed and the head must be born in a state of extreme extension (Fig. 21.4). These circumstances lead to a significant slowdown in the course of the second stage of labor and, as a consequence, to asphyxia, injury to the fetus and even death.

It is necessary to identify in advance a group of pregnant women with breech presentation of the fetus who have indications for performing a planned caesarean section. These indications include:

· anatomically narrow pelvis and abnormal pelvic shapes;

· extension position of the fetal head;

· foot presentation of the fetus;

· posterior view of breech presentation of the fetus;

· mixed breech presentation in first-time mothers;

· fetal weight more than 3500 or less than 2000 g;

· placenta previa and its low location;

· umbilical cord presentation;

· scar on the uterus;

· cicatricial changes in the cervix, vagina and perineum;

· elimination of a history of genitourinary and enterogenital fistulas;

· pronounced varicose veins in the vagina and vulva;

· severe gestosis;

· hemolytic disease of the fetus;

· delayed fetal development;

· pronounced FPN (subcompensated or compensated form);

· severe concomitant extragenital diseases;

· large uterine fibroids;

· abnormalities of the uterus;

· lack of biological readiness of the body for childbirth during full-term pregnancy;

· lack of effect from preparing the cervix for childbirth;

· post-term pregnancy in combination with an “immature” cervix;

· the age of the first-time mother is over 30 years;

· complicated obstetric history (infertility, recurrent miscarriage, birth of a sick, injured child, premature birth with death of newborns, stillbirth);

· the onset of this pregnancy after the use of assisted reproduction methods.

Rice. 21.4. Delay of the fetal chin above the pubic symphysis in the posterior form of breech presentation.

Presentation of the fetal scrotum. Touch during vaginal examination, mechanical irritation that occurs during fetal advancement, birth of the scrotum with high-lying buttocks and legs, thermal and painful irritation cause premature breathing and aspiration of amniotic fluid, which often contains meconium. It has been noted that boys born in a breech presentation through the natural birth canal often subsequently experience infertility due to testicular trauma during childbirth. Unfortunately, with breech presentations, it is not always possible to reliably determine the sex of the fetus using echography before birth. However, if a male fetus is identified and there are other aggravating circumstances for breech presentation, then it is advisable to resolve the issue of delivery by cesarean section as planned. In the case of vaginal delivery, a protracted course of the second stage of labor should be avoided. It is necessary to remove the fetus as quickly and carefully as possible, followed by appropriate care for the newborn.

G tinthe fetus in some cases enters the entrance to the pelvis in a state of extension. Depending on the degree of extension, one or another version of insertion occurs: anterior cephalic - moderate extension, frontal - medium degree of extension, facial - maximum extension.
Factors contributing to the formation of extensor insertions include deviations from the norm in the shape and size of the pelvis (simple flat, planar-rachitic pelvis), decreased tone of the muscles of the uterus, in particular its lower segment, decreased tone of the fetus, the presence of a large or small size of the fetal head . Extensor insertions can be caused by a violation of the articulation of the fetus (for example, throwing the arms behind the neck), or structural features of the atlanto-occipital joint, which make it difficult to flex the head. Possible causes of extensor presentations are polyhydramnios and multiple pregnancies. The condition of the abdominal press plays a certain role. A saggy abdomen and displacement of the uterus to the side (usually to the right) lead to the fact that the axis of the uterus and the axis of the fetus do not coincide with the axis of the pelvis. As a result of this, the head moves to one of the lateral sections of the pelvis, and if the fetal body deviates towards the back of the head, the chin moves away from the chest and extension of the head occurs. In addition, skeletal deformation in the mother (kyphosis) can contribute to extension of the head.
Childbirth with anterior cephalic presentation usually occurs in the posterior form.
Diagnosis of this type of insertion is based solely on vaginal examination data. As a rule, the sagittal suture is located in the transverse dimension (extremely rarely in the oblique dimension) of the plane of the entrance to the pelvis. The large fontanelle (leading point) is determined along the wire axis of the pelvis, but the small fontanel is not reached.
1st moment - insertion of the fetal head occurs with a sagittal suture in the transverse, less often in the oblique, size of the entrance to the pelvis. The head is in a slightly extended state; it is installed in the plane of the entrance to the pelvis with a fronto-occipital size of 12 cm.
2nd point - moderate extension of the head, as a result of which the leading point becomes the large fontanel. The small fontanelle lags behind in forward movement.
3rd moment - sacral rotation carried out, as usual, in the plane of the entrance to the small pelvis. In this case, the anterior parietal bone descends first, going beyond the posterior one, then the posterior one, and finally, the entire head ends up in the wide part of the pelvic cavity. The frontal and occipital bones may be displaced under the parietal bones.
4th moment - internal rotation of the head is carried out in the pelvic cavity so that the large fontanelle turns towards the pubic joint.
5th moment — flexion and extension of the head occurs in the plane of exit from the pelvis, where the head makes two movements. The area of ​​the bridge of the nose fits under the lower edge of the symphysis, and the first point of fixation is formed. Around it, the head bends, as a result of which the crown and back of the head are released from under the perineum (Fig. 44, A). After this, a second point of fixation is formed - the occipital protuberance, around which the head is extended, and the forehead and face of the fetus are born (Fig. 44, b). The head erupts with a straight size - fronto-occipital, equal to 12 cm. The circumference passing through it is 34 cm. The birth tumor is located in the area of ​​the large fontanel. The shape of the skull is brachycephalic - a “tower” skull (Fig. 45).
6th And 7th moments The biomechanism of childbirth occurs in the same way as with an occipital presentation.
FRONTAL PRESENTATION is rare (in 0.04-0.05% of all births). It occurs during labor, when the head, moving forward with the forehead, lingers in this position. The chin cannot drop due to one reason or another. If the fetal head is pressed or fixed by a small segment at the entrance to the small pelvis and the amniotic fluid has not been poured out, the frontal insertion may turn into the facial one. After the rupture of amniotic fluid and fixation of the head with a large segment, the frontal insertion does not change.
The diagnosis of frontal presentation is made exclusively according to vaginal examination: the forehead is determined along the pelvic axis; in the transverse dimension of the plane of the entrance to the small pelvis there is a frontal suture; on the one hand, the bridge of the nose and brow ridges of the fetus are determined, on the other, the anterior angle of the large fontanel. The large fontanel is located on the side corresponding to the back of the fetus.
1st moment biomechanism of childbirth lies in the fact that the fetal head in frontal presentation is inserted into the inlet of the pelvis with a large oblique size equal to 13.5 cm, with a circumference corresponding to 39-40 cm. The frontal suture is located in the transverse size of the inlet. Already at this stage, a disproportion between the size of the head and the size of the entrance to the pelvis is revealed. Promote furtherThe movement of the head stops, and the birth has to be completed by caesarean section.

Rice. 44. Biomechanism of labor during cephalic presentation:

a — bending of the head around the first point of fixation; b - extension of the head

around the second fixation point

If the fetus is premature and small in size, then 2nd mo- cop biomechanism of childbirth- extension of the head, as a result of which the center of the forehead is established along the axis of the pelvis and the lowest.

3rd point - sacral rotation is carried out in the same way as with occipital presentations.

4th moment - internal rotation of the head is carried out at 90°, while the frontal suture passes from the transverse size of the pelvis to the oblique, and then to the straight. The wings of the nose are directed towards the symphysis.

At the 5th moment biomechanism of childbirth the head makes two movements. As soon as the upper jaw approaches the lower edge of the symphysis (the first point of fixation), the head begins to bend and is born to the occipital protuberance, which is fixed at the apex of the coccyx, around which the head begins to unbend: the upper and lower jaws are born.

6th and 7th moments — do not differ from the corresponding moments of the biomechanism of labor during occipital presentation. The fetal head is born with a circle midway between the large oblique and straight circles. The circumference is 35-36 cm. The birth tumor is located on the head, occupying the entire forehead and spreading in one direction to the eyes, in the other to the large fontanel. In profile, the head has the shape of a triangle with the apex at the forehead (Fig. 46).

Childbirth in a frontal presentation is the least favorable among births in an extension presentation.

FACIAL PRESENTATION OF THE FETUS - a presentation in which instead of the back of the head, the face of the fetus comes first. It occurs in 0.25% of births. Facial

Rice. 45. Brachycephalic form Rice. 46. ​​Head shape

fetal head (the dotted line indicates with frontal presentation

Chena normal head shape)

presentation is the maximum degree of extension (Fig. 47). The fetal head with it, just like with the occipital one, has a bean-shaped shape. A favorable mechanism for the passage of the head is created when the line of the head curvature coincides with the line of curvature of the birth canal. This coincidence is possible in the posterior view, when the fetal chin is facing anteriorly. In this case, the head passes through the cross sections of the birth canal with the same planes of cross sections inclined fan-shaped to each other, as in the case of occipital presentation, but only in the reverse order.
The diagnosis of facial presentation can be made by external, or more accurately, by vaginal examination. During external examination, it is determined that the back of the head, which protrudes from the side above the pubis, is thrown back and almost pressed against the back of the fetus. In this case, an acute angle is formed between the back and the back of the head. The back extends far from the wall of the uterus, and the curved chest of the fetus approaches it. Therefore, the fetal heartbeat can be heard more clearly not from the side of the back, but from the side of the fetal chest, i.e., where small parts of the fetus are palpated: in the first position - on the right below the navel, in the second position - on the left below the navel. During a vaginal examination, the chin and mouth are felt on one side, and the root of the nose and brow ridges on the other. All these identification landmarks are easily determined before the water breaks and after the water breaks before the formation of the birth tumor. In the presence of a birth tumor, diagnostic errors are possible. Facial presentation can be mistaken for breech presentation.
Facial presentation can be primary if it is established during pregnancy in the presence of a congenital goiter or neck tumor in the fetus, and secondary if it develops during childbirth from a frontal presentation.
IN 1st moment the fetal head is inserted into the inlet of the small pelvis with a vertical dimension. The facial line is located in a transverse or oblique dimension

Rice. 47. Facial presentation, longitudinal position of the fetus, first position

A — back view ; b — front view

plane of entry into the pelvis. The chin and the large anterior fontanel are at the same height.

In 2nd moment biomechanism of childbirth, instead of the usual flexion, the fetal head extends as much as possible. The chin falls lower than the large genus. In this position, the fetal face descends into the pelvic cavity. The cheek facing the anterior wall of the pelvis is easier to reach during examination than the cheek facing the sacral cavity.

3rd moment — sacral rotation occurs easily.

4th moment — the head makes an internal rotation, caused by the same factors that determine this moment of the biomechanism of labor during occipital presentation (Fig. 48, A). The facial line becomes the direct dimension of the exit plane, and the chin appears under the pubic joint (Fig. 48, b).

If internal rotation is impaired, the fetal chin may turn toward the sacrum, i.e., the fetal back turns anteriorly. Childbirth in the anterior form of facial presentation is suspended.

Rice. 48. Biomechanism of labor during facial presentation:

A— internal rotation of the head; b — internal rotation of the head is completed;

V — birth of the head

With the chin facing anteriorly, the 5th begins stage biomechanism of childbirth. The face is lowered until the chin erupts, and the angle between the lower jaw and the fetal neck approaches the lower edge of the symphysis. A fixation point is formed - the hyoid bone, around which the head bends. The forehead, crown and back of the head are born sequentially (Fig. 48, c).

Internal rotation of the body and external rotation of the head, the birth of the shoulder girdle and the entire fetus occur in the same way as with occipital presentations.

The eruption of the head occurs in a circle corresponding to the vertical size (diameter - 9.5 cm, circumference - 32 cm). The birth tumor is located on the half of the face facing anteriorly (chin, lips). The shape of the head is sharp dolichocephalic. Childbirth in the posterior form of facial presentation proceeds favorably: most of them end spontaneously (90-95%).

Extensor presentation of the head occurs in 0.5-1% of births -

the head is inserted straight into the entrance to the pelvis.

There are 3 extension options: anterocephalic, frontal and facial. The extension presentation option is determined by the leading point and the size by which the head passes all planes of the pelvis (Table 14.1).

Table 14.1. Variants of extension presentations of the head.

Extensor presentation of the head occurs both before and during childbirth. They usually have no practical significance during pregnancy, since they disappear spontaneously with the onset of labor. Only in extremely rare cases, with a large goiter or extensive cystic hygroma of the fetal neck, as well as with large submucosal uterine fibroids, does an extensor presentation of the fetus occur both during pregnancy and during childbirth.

During childbirth, each option of extension presentation is not stable. It can change, transform, bending or unbending, into other previous and subsequent variants of presentation. For example, the anterior cephalic becomes occipital when the head is flexed, the frontal becomes facial when extended, etc.

The most unfavorable option is frontal presentation, since the head passes the plane of the pelvis with a large oblique size, which even with a small fetus leads to significant difficulties in childbirth. Childbirth is possible only with a very low fetal weight.

The principle of the mechanism of labor during extensor presentation is as follows.

The first point is that extension occurs in the plane of the entrance to the pelvis; in the plane of the wide part, internal rotation of the head occurs with the formation rear view(anterior delivery is not possible, since the occipital part of the head must use the sacral cavity). In the plane of the narrow part of the pelvic cavity and the exit, the rotation ends and the sagittal suture (anterior cephalic presentation) or the facial line (frontal or facial presentation) is established in a straight size. Subsequently, first the first point of fixation is formed under the pubis and the head bends, and then the second - the head unbends

ANTEROCEPTICAL PRESENTATION

Anterior cephalic presentation consists of first degree extension. Compared to the occipital presentation, the head passes through a large size (a large segment passes through the direct size of the head - 12 cm), the leading point is the large fontanel.

Diagnostics carried out during vaginal examination from the beginning of inserting the head into the entrance to the pelvis. In the first stage of labor, when the cervix is ​​dilated by 2 cm or more, it can be revealed that the sagittal (sagittal) suture is located more often in a transverse or slightly oblique dimension, and the fontanelles, large and small, are at the same level. If the sagittal suture is located obliquely, then the large fontanel is located in front. Often a certain asynclitism is detected - the first to enter the entrance to the pelvis is the parietal bone, facing anteriorly, and the sagittal suture deviates posteriorly.

If childbirth occurs through the natural birth canal, then the shape of the head can confirm this variant of presentation - the head has a brachiocephalic shape.

Mechanism of childbirth.First moment of birth- moderate extension of the head occurs at the entrance to the pelvis. The second moment of childbirth - internal rotation the head is carried out in a wide part of the pelvic cavity with the formation of a posterior view. The rotation ends in the pelvic outlet cavity, the sagittal suture is set to a straight size. After this it begins third moment of labor - flexion of the head after the formation of the fixation point, the region of the glabella approaches the lower edge of the womb, and parietal tubercles are born from behind the perineum. The back of the head forms the second point of fixation, resting against the tailbone. Head extension occurs after the formation of the second fixation point - fourth moment of birth. The facial part is born from under the womb. The fifth moment of labor - internal rotation of the shoulders and external rotation of the head, occurs in the same way as with occipital presentation.

Course and management of labor. Due to the lack of a fitting belt, prenatal rupture of amniotic fluid often occurs. The protracted course of the first and second stages of labor can lead to hypoxia and trauma to the fetus.

Anterior cephalic presentation requires an individual approach to choosing the method of delivery. The ratio of the sizes of the pelvis and head should be carefully assessed. If there is doubt about their proportionality, a cesarean section should be performed, especially if, with full dilation of the cervix, there is a tendency to form an anterior view or there is no advancement of the head. Caesarean section is also indicated for postterm pregnancy. In case of weak labor or fetal hypoxia, when the head is located in a narrow part of the pelvic cavity, vacuum extraction is indicated, and when located at the pelvic outlet, episiotomy is indicated.

FRONTAL PRESENTATION

Frontal presentation is very rare (0.021-0.026%. A large segment of the head in frontal presentation passes through a large oblique dimension (13.5 cm), which is largest in extension presentations. Frontal presentation (II degree of extension) is often a transitional state from anterior cephalic to facial.

Diagnosis of frontal presentation using external techniques is difficult. One can only assume a frontal presentation based on the high position of the uterine fundus and the angle between the back of the head and the back of the fetus. The fetal heartbeat is best heard from the chest rather than the back. During a vaginal examination, the frontal part of the fetal head is determined: the frontal suture is palpated, which ends on one side with the bridge of the nose (the brow ridges and orbits are also determined), on the other -

a large fontanel.

After birth, the configuration of the head can confirm the frontal insertion. The birth tumor, located in the forehead, gives the head a peculiar appearance of a pyramid or tower (Fig. 14.1).

Mechanism of labor(Fig. 14.2). The first moment of labor is extension in the plane of the entrance to the pelvis. The frontal suture is usually located transversely. The leading point is the frontal bones, on which a pronounced birth tumor forms during childbirth. As the head moves further, it begins second moment of labor - internal rotation of the head, which ends in the exit plane. In this case, the fetus turns its back backwards, the frontal suture is located in a straight dimension. The third moment of childbirth is flexion of the head. The upper jaw is pressed against the lower edge of the symphysis pubis, forming the first point of fixation. There is flexion of the head and birth of the crown and occiput of the fetus. The fourth moment is extension of the head- begins after the formation of the second point of fixation - the suboccipital fossa, resting on the top of the coccyx. Around this fixation point, the head is extended, as a result of which the head is born completely. Fifth point - internal rotation of the shoulders(and external rotation of the head) occurs in the same way as with other types of cephalic presentation.

Course and management of labor. With frontal presentation, untimely rupture of amniotic fluid often occurs due to the lack of an internal sealing belt.

Childbirth with a frontal presentation can occur in the posterior view only if the fetus is very small and the pelvis is large. Childbirth is also possible if the frontal presentation at the entrance to the pelvis turns into a facial one. If the pelvis is of normal size and the fetus is of average size, childbirth through the birth canal is impossible; a caesarean section should be performed. Delay in surgery can lead to uterine rupture due to the resulting clinically narrow pelvis. In case of fetal death during childbirth, perforation of the head is indicated.

FACIAL PRESENTATION

Facial presentation, as a rule, occurs during childbirth and is the result of maximum extension of the head. Of all the extension presentations, the facial one (III degree of extension) is the most favorable, since the large segment passes through a vertical dimension of 9.5 cm. The leading point is the chin. With neck tumors and repeated entanglement of the umbilical cord, facial presentation occurs during pregnancy. Facial presentation can be formed from frontal presentation when extension increases during childbirth.

Diagnostics. Facial presentation can be suspected during the fourth appointment of an external obstetric examination, when the head is located in the plane of the pelvic inlet. A pronounced depression is determined between the wall and the back of the head, and on the opposite side a sharp protruding part, the chin, can be palpated.

The fetal heartbeat is better heard from the chest. Ultrasound clearly shows an extensor presentation.

During vaginal examination and dilation of the cervix by 2-3 cm, the chin, mouth, nose, and brow ridges are determined. Sometimes facial presentation is differentiated from purely gluteal presentation, when the anus is mistaken for the mouth, and the coccyx and ischial tuberosities are mistaken for the facial bones. With a facial presentation, as well as with a pelvic presentation, the examination must be careful, since with a facial presentation the eyes can be damaged, and with a pelvic presentation, the genitals of the fetus can be damaged.

The position and type of the fetus is easier to determine by the chin, which is directed in the opposite direction to the back. If the chin is determined on the left and in front, then the fetus has a posterior view, the second position.

Mechanism of labor(Fig. 14.3). The first moment is maximum extension of the head- occurs in the plane of the entrance to the pelvis. As a result, the chin becomes the leading point. The facial line passing through the frontal suture and nose is set in one of the oblique dimensions of the pelvis or in the transverse one. With a facial presentation, the head is the smallest size (9.5 cm) of all extension presentations. The second point is the internal rotation of the head, which begins at the transition to the wide part of the pelvic plane with the formation of the posterior view. Only at birth in the posterior view can the occiput be placed in the sacral cavity. In the anterior view, childbirth is impossible! The internal rotation ends in the plane of exit from the pelvis. The third moment of the labor mechanism in the posterior form of facial presentation is flexion of the head occurs after the formation of a fixation point - The hyoid bone is located under the pubis. First, a swollen chin and lips appear from the genital cleft, and then the occipital part is born. The fourth point is the internal rotation of the shoulders(and external rotation of the head) occurs in the same way as with other types of cephalic presentations.

Course and management of labor. Childbirth is often complicated by premature rupture of amniotic fluid (absence of the attachment belt) and becomes protracted. With normal pelvic sizes and average fetal sizes, labor ends favorably for the fetus, but takes longer than with an occipital presentation, since maximum extension requires more time than flexion. Perineal ruptures are more common than with occipital presentation, since the occipital part of the head is not configured.

Management of labor in a face presentation with a normal pelvis and a small fetus should be expectant. It is necessary to constantly monitor labor and the fetal heartbeat.

In the first stage of labor, careful monitoring of the preservation of the posterior view is mandatory, since in the event of an anterior view, childbirth through natural means is impossible and a cesarean section must be performed.

Caesarean section is also indicated when signs of a clinically narrow pelvis, fetal hypoxia, weakness of labor, and umbilical cord prolapse appear.

In case of vaginal delivery and the threat of perineal rupture, an episiotomy is performed.