Caesarean section with preterm pregnancy

As is known, at present the problem of "birth trauma" in medicine is given great importance. Therefore, despite extensive knowledge in this field, the individual risk of spontaneous delivery in preterm pregnancy is often underestimated only because it is difficult and unusual to consider this complex process based on the category of "trauma."

Thanks to modern methods used in obstetrical practice (echography, computed tomography) it was shown that even in the antenatal period, before the onset of labor, cerebral hemorrhages are possible. At the same time, it was possible to obtain scientific evidence of the origin of intracranial hemorrhages as a result of the direct impact of birth pains on the fetal skull in the process of the birth act. Thus, the effect of intrauterine pressure on the fetal head in the II stage of labor can reach 15 kg.

Some foreign authors believe that physiopathologically and neurosurgically does not pass through labor without a hidden craniocerebral trauma, i.e. Without repeated changes under pressure in the cerebral and facial skull, the base of the skull and the cranio-cervical transition to the axial organ of the spinal column with accompanying disturbances of the macro - and microcirculation. The embryonic brain from the moment of its appearance has fully developed "differentiated neurons and in no case represents a formless homogeneous mass. Therefore, irreversible circulatory disturbances can occur in the entire cranial-cerebral region with extensive subdural and intraventricular hematomas and intraocular hemorrhages.

Simultaneously, the onset of microcirculatory acidosis turns into a life-threatening cerebral edema. The tremendous workload during childbirth on the fetus can manifest itself in the form of a disease only many years later.

Depending on the length of service and the experience of the doctor, the frequency of cesarean section in a full-term pregnancy has significant variations. When considering the issue of expanding the indications for cesarean section surgery in case of premature pregnancy, it is important to take into account the death rate of parturient women and puerperas in preterm labor, which according to the research was 26.8% of the total number of pregnant, maternity and puerperal deaths in the country. The leading causes of death were late toxicosis (26.8%), extragenital diseases (23.4%), bleeding (21.9%), sepsis (12.4%).

41.4% of women with late toxicosis were delivered by a cesarean section; With extragenital pathology, 13.4% are delivered by a cesarean section. It should be noted that the overwhelming majority of women (61.8%) were delivered by the operation of cesarean section. At the same time, the analysis of lethal outcomes in preterm labor showed that 93.4% of women died after childbirth. Thus, the operation of cesarean section in case of premature pregnancy, as in case of urgent childbirth, remains a high-risk intervention in terms of maternal mortality and morbidity.

The results of the scientific analysis of perinatal mortality show that the main causes of it are fetoplacental insufficiency in a number of pregnancy complications and extragenital diseases (especially diabetes mellitus), birth trauma and the combination of birth trauma with respiratory failure and lung atelectasis, as well as fetal malformations. Knowing these main causes of perinatal mortality makes it possible to identify reasonable ways to reduce them both in the ante- and intranatal and postnatal periods. In particular, attempts are being made to study the effect of the active phase of labor and the method of delivery on the frequency of intracranial hemorrhages. A number of studies have shown that the overall frequency of hemorrhages developed during the first 7 days of life was approximately the same as those inflicted by cesarean section surgery in the early and late periods of the birth act, but the timing of their occurrence was different. In most children, extracted by cesarean section before the active phase of childbirth, hemorrhages developed within the first hour of life. In children, delivered during the active phase of childbirth, progression of hemorrhages up to grade III-IV was observed irrespective of the mode of delivery.

In earlier works, the issue of the operation of caesarean section with pelvic presentation at premature births and the presence of twins with fruits weighing less than 2500 g, if one of them is in the pelvic presentation, was discussed. So, for example, if the operation of cesarean section with pelvic presentation of the fetus and the gestation period of 32-36 weeks was carried out with a mass of fruits of 1501 to 2500 g, the number of newborns that died after the operation was 16 times less than in premature births through natural birth canals. It is important to note that the state of newborns born by cesarean section was significantly better.

In this case, the severe and moderate degree of asphyxia was 2.5 times less in the group of children given birth by cesarean section. Therefore, it is recommended that this operation be more widely used in preterm labor. Other authors, despite the increase in the frequency of cesarean section operation with pelvic fetal presentation and premature birth, did not discern differences in the state of children weighing 1501 to 2500 g compared to children born through natural birth canals. Therefore, a number of midwives believe that the reduction of perinatal mortality should occur due to the prevention of preterm labor, continuous monitoring of the fetus.

According to modern data, the frequency of cesarean section with preterm pregnancy is about 12%. In almost half the cases, it is carried out in a planned manner, every fifth woman - in connection with bleeding and pelvic presentation of the fetus or its hypotrophy. At half of women operation is spent in the course of the generic certificate. Most authors now tend to consider a very low body weight (less than 1500 g) in a caesarean section that merits further study. Noteworthy are the outcomes of cesarean delivery up to 32 weeks gestation. In this case, the main indications for surgery are: acute fetal dysfunction, chronic hypoxia, premature birth in itself, multiple pregnancy and unavoidable premature birth, mother's diseases, combined indications. About 70 % of babies born before 32 weeks of gestation had normal psychomotor development when observed up to 5 years. The advantages of operative abdominal delivery in case of preexisting with the presence of pelvic fetal presentation are convincingly shown. Some authors believe that the outcome of the operation for the newborn affects the incision on the uterus, since with gestational periods of 26-32 weeks and the weight of the fetus from 501 to 1500 g, extremely careful delivery is necessary. At the same time, during these periods, a poor deployment of the lower segment of the uterus is observed, and the head circumference at 28 weeks is 25 cm and about 30 cm at 32 weeks gestation, the length of the fetus is 23 cm at 26 weeks and 28 cm at 32 weeks gestation.

At the same time, some authors believe that premature newborns, extracted by cesarean section, have a number of characteristics during the neonatal period. The outcome of the operation for the fetus is determined by the complications of pregnancy, the presence and condition of the scar on the uterus, extragenital diseases of the mother, and the degree of maturity of the fetus. It is believed that in modern conditions cesarean section in case of premature pregnancy, and especially in the presence of a scar on the uterus, should be carried out only on strict indications from the mother.

Despite the fact that many authors refrain from cesarean section with pelvic presentation and fetal weight less than 1500 g, nevertheless it should be noted that the frequency of postnatal death of children is 2 times less in cesarean section, and the frequency of low Apgar scores and intracranial hemorrhage is not different in both groups. The greatest frequency of surgery was with a gestation period of 29-34 weeks. At the same time, it was noted that doctors do not have the opportunity to learn to take births with pelvic presentation of the fetus, since for each trainee every year there are two births with a pelvic presentation of the fetus. Therefore, the frequency of cesarean section with pelvic presentation may increase in the future and reach 100%. At present, with breech presentation, all births must end with a caesarean section operation. However, there was no significant correlation between the rates of perinatal mortality and the rate of cesarean section. Therefore, and up to the present time, the problem is acute - whether the cesarean section reduces the risk of delivery during premature delivery of the fetus in pelvic presentation.

Thus, the use of caesarean section does not reduce the incidence of hypoxia, birth trauma, encephalopathy or neonatal mortality. Therefore, it is concluded that with preterm delivery in a pelvic presentation, caesarean section at 29-36 weeks does not have advantages over delivery through natural birth canals. Operation up to 29 weeks in most cases can be justified. It has also been established that fetal malformations and fetal respiratory distress are more often noted in pelvic presentation of the fetus.

The issue of morbidity and mortality among preterm infants born in the pelvic presentation with a birth weight of 1500 g or less, depending on the mode of delivery (vaginal or abdominal delivery) is worthy of attention. In a few studies based on a small number of observations, it is concluded that the impact of the method of delivery on infant mortality has not been revealed. The causes of infant mortality in both groups were intracranial hemorrhages and extreme immaturity. Objective research methods (pH value in the blood of the umbilical cord, Apgar score, etc.) show that the newborns recovered by the operative route had better adaptation parameters compared with the children who had vaginal delivery. These studies indicate the beneficial effect of timely and gentle delivery by caesarean section on the incidence of low birth weight infants born in the pelvic presentation. In particular, the caesarean section may reduce perinatal mortality in newborns by 50% in pelvic presentation and low body weight. In addition, children recovered by cesarean section had a lower incidence compared to children born through natural birthmarks. Therefore, conclusions are drawn even on the expansion of indications for abdominal delivery in children with low birth weight.

Great attention is paid to issues related to the management of pregnancy and childbirth in multiple pregnancies. In a number of modern works, the question is raised whether the increase in the frequency of a cesarean section would improve the conditions for the existence of children at birth. It is necessary to emphasize the fact that after 35 weeks of pregnancy the neonatal outcome for the second fetus does not depend on the method of delivery. Other authors believe that if the second fetus is not in the head presentation, then it is necessary to perform a caesarean section operation, even under conditions if the first fetus was born through natural birth canals. A number of researchers believe that with a mass of children over 1500 grams, deliveries through natural birth canals are also safe, as in the operation of cesarean section. However, some authors believe that extraction of the fetus beyond the pelvic end of the second fetus with a mass of more than 1500 g is the most appropriate alternative to cesarean section and external rotation. Therefore, the optimal choice of the method of delivery of the second of fetal twin remains a controversial issue of modern midwifery. The outward turn of the second fetus in pelvic presentation from twins is a relatively new achievement in the management of a multiple pregnancy. However, in a number of studies it has been shown that the external turn is associated with more failures than the extraction of the fetus by the pelvic end. At the same time, there was no difference in neonatal mortality with these methods of delivery. Thus, extraction of the fetus from the pelvic end of the second fetus from twins weighing more than 1500 g is an alternative to cesarean section or external rotation. However, so far there is little comparative research on this issue. This is probably due to the lack of work on the development of the fetus in twin pregnancies. The development of the fetus during twin pregnancy is influenced by such parameters as the state of the chorion and the presence of interplanar anastomoses in the placenta in the case of monozygotic twins. It is noted that with a twin pregnancy at 32-34 weeks, the fetal growth slows down. Thus, the body weight of newborn twins is 10% less than the weight of the fetus in single pregnancy. Decreased growth rates can affect both the twins and one of them, and this difference can be 25%. The slowing of the development of the fetus affects primarily the length and mass of the baby's body. When studying the status of newborns taken by caesarean section, it is necessary to take into account the effect of anesthesia and the duration of the interval: the incision of the uterus - delivery to the state of the newborn. At the same time, if the duration of this interval was less than 90 s, acidosis was more pronounced under conditions of epidural analgesia. With the prolongation of this interval under conditions of general anesthesia, there was also an increase in acidosis. To reduce the traumatism of newborns, especially those with low weight, currently in the technique of cesarean section, great importance is attached to the vertical section of the uterus in the region of its lower segment, especially in the transverse position, placenta previa, in the production of hysterectomy and the presence of uterine fibroids in its lower segment. Especially relevant this issue remains with the extraction of the fetus with a mass of 1000-1500 g (isthmic-corporal with longitudinal incision of the uterus).

It is important to recognize that the increase in the frequency of cesarean section surgery in premature pregnancy is increasingly based on neonatological indicators - immaturity, perinatal infection, the risk of birth trauma for the mother, fetus and newborn. Therefore voices are voiced in defense of the provision that caesarean section should not be performed before 32 weeks of pregnancy.

For prognostic evaluation of preterm fetuses and fetuses with hypotrophy (a sharp delay in fetal growth): with a delay in fetal growth, the survival rate of children in cesarean section is now almost 40%, and in case of premature birth - 75%. The main causes of death were placenta previa (30%), malformations of the fetus, polyhydramnios, rhesus-conflict. In general, the risk of mortality for fetuses weighing less than 1500 g is significantly higher in vaginal delivery than in cesarean section. The prognosis for a fetus with a gestation period of less than 28 weeks is usually uncertain, with a gestation period of 28-32 weeks - more favorable. It is important to emphasize that the risk of developing a respiratory distress syndrome in newborns is proportional to the duration of pregnancy and, possibly, higher in newborns that are delivered by a cesarean section than with delivery through natural birth canals.

In the literature, there are indications of an increased risk of developing respiratory distress syndrome depending on indications for cesarean delivery, including prenatal bleeding, diabetes mellitus, abnormal cardiotocogram in the fetus, and toxicosis of pregnant women. Respiratory distress syndrome increases as the weight of the baby decreases: at 1000-1499 g - 25%; 1500-1999 g - 14%; 2000-2499 g - 7.1%.

Thus, the need for rapid delivery with preterm birth occurs in almost 75% of cases before the onset of labor.

The main indications for cesarean section from the side of the fetus are:

• fetal hypoxia, mainly due to fetoplacental insufficiency due to late toxicosis, especially in combination with diabetes mellitus;
• pelvic presentation of the fetus with the appearance of symptoms of disruption of life.

Almost 50% of cesarean sections with preterm pregnancy are performed with the beginning of labor. The most frequent indications for him are:

• transverse and oblique position of the fetus;
• deterioration of the fetus against extragenital pathology (mainly diabetes) in parturient women;
• threatening rupture of the uterus;
• ineffectiveness of induction in the discharge of amniotic fluid.

In conclusion, it should be noted that perinatal mortality in cesarean section in women with premature pregnancy is only 1.3 times higher than perinatal mortality in vaginal births (with full term pregnancy, perinatal mortality is 3-6 times higher in cesarean section than in natural delivery birthmarks).

The highest perinatal losses are observed among newborns with a body weight of 1500 g or less, both during operative delivery and at delivery through the natural birth canal, with perinatal mortality rates in both cases almost identical and exceeding 75% during all years of follow-up. This means that in the absence of a developed highly skilled neonatal service, a child's weight of 1500 grams or less is a relative contraindication to abdominal delivery in the interests of the fetus, a cesarean section in such conditions should be carried out mainly according to the vital indications from the mother.

Thus, women with preterm labor should be referred to a high-risk group. They have a history of miscarriage, artificial termination of pregnancy, abnormalities of genital organs, extragenital diseases. Therefore, in the group of women with various obstetric complications, the frequency of preterm labor is higher. Labor should be performed in a specialized obstetric hospital, where there are opportunities to prevent possible complications from the mother and fetus.

[1], [2], [3], [4], [5], [6], [7]