Perinatal Lesions of the Central Nervous System in Premature Newborns Complicated Labor Depending on the Method of Delivery

The dissertation is devoted to the study of perinatal lesions of the central nervous system in premature newborns arising in the context of complicated labor and their dependence on the method of delivery — cesarean section or natural birth. The research is conducted at the Moscow Research Institute of Pediatrics and Pediatric Surgery and includes a comparative analysis of the frequency, severity, and outcomes of CNS lesions during the early neonatal period in children born by different methods. The study evaluates the influence of complications of pregnancy and the labor process, such as intrauterine hypoxia, fetal pelvic presentation, and gestosis, on the development of perinatal pathology, and also examines the role of operative delivery in the prevention of severe neurological consequences.

Reducing morbidity and perinatal mortality among premature children is an urgent task of modern perinatology and pediatrics. The most common cause of morbidity and mortality is perinatal lesions of the central nervous system (CNS), caused not only by impaired intrauterine fetal development but also by complications of pregnancy and the labor process. Severe acute fetal hypoxia and neonatal asphyxia, in most cases, are complications of the labor process [25, 5].

In connection with this, in recent years there has been a trend toward delivery by cesarean section for premature complicated births associated with the probability of severe CNS damage to the fetus or a fatal outcome. The main indications for abdominal delivery in the interests of the fetus are acute or chronic intrauterine fetal hypoxia, pelvic presentation (breech or footling), transverse fetal position, placental abruption, and severe forms of gestosis [27, 31, 23, 1, 2]. Opinions of specialists regarding cesarean section in the prevention of morbidity and mortality in term infants, under certain complications, coincide [24, 92, 79, 80]. As for premature children, despite a sufficient number of studies devoted to this question, the data are quite contradictory. A number of works note an improvement in the prognosis of neuropsychological development and a reduction in mortality among premature children born by cesarean section compared with children born naturally under the same complications in labor [90, 139, 137, 8, 1,61, 106].

However, other authors do not share the opinion on expanding the indications for operative delivery in the interests of the fetus, believing that the high morbidity rate among premature children is determined to a greater extent by the severity of intrauterine fetal distress, the degree of prematurity, immaturity, timeliness, and quality of medical care after birth [98, 45, 56, 85, 126,81].

The question of whether cesarean section is an intranatal risk factor for the fetus and newborn remains controversial. Some scientists believe that operative delivery, excluding physiological birth stress, causes in newborns during the early neonatal period a violation of respiratory adaptation and cardiac activity [105, 20]. According to A.S. Slepukh (1986), the impairment of health in these children is determined not so much by the influence of the operation as by the pathology of pregnancy and labor that were indications for performing operative delivery.

The small number of studies addressing the influence of various complications in labor and the method of delivery on morbidity and mortality in children during the early neonatal period and long-term outcomes, from the standpoint of neonatology, pediatrics, and neuropathology, do not allow a unified opinion to be reached. Given that the possibilities of treating the consequences of perinatal lesions of the CNS are in many cases limited, the problem of preventing severe CNS lesions becomes obvious [25].

It seems important to determine the causes of the occurrence of perinatal lesions of the CNS and their influence on the further development of premature children born naturally and by cesarean section.

Research Objective

Determination of the frequency, degree of severity, and outcomes of perinatal lesions of the CNS in premature children depending on the method of delivery, in order to substantiate methods for the prevention of perinatal morbidity and mortality and to improve the prognosis of neuropsychological development.

Research Tasks

1. To identify features of adaptation during the early neonatal period in premature newborns born naturally and by cesarean section.

2. To conduct a comparative study of the frequency and severity of perinatal lesions of the CNS during the early adaptation period in premature children born naturally and by cesarean section.

3. To establish the relationship between the degree of severity of CNS lesions, the level of lactate in the blood, and the dynamics of activity of lymphocytic dehydrogenases in children born naturally and by cesarean section.

4. To conduct a comparative analysis of the consequences of perinatal lesions of the CNS in children depending on the method of delivery.

Scientific Novelty

Based on the conducted comparative analysis of the early adaptation period of premature children born by different methods of delivery, it has been found that severe disturbances of adaptation processes after operative delivery are caused not so much by the absence of birth stress and the influence of the operation itself as by complications of pregnancy that were indications for cesarean section.

It has been established that in the presence of acute or chronic intrauterine hypoxia, abnormal fetal presentations (breech or footling), and birth weight exceeding 1500 g, the frequency and severity of perinatal lesions of the CNS and fatal outcomes among premature children during the early neonatal period are reliably reduced by delivery by cesarean section.

It has been revealed that the smaller the gestational age and the more severe the degree of CNS damage, the lower the activity of lymphocytic dehydrogenases — succinate dehydrogenase (SDH), alpha-glycerophosphate dehydrogenase (a-GPDH), and glutamate dehydrogenase (GDH). At the same time, severe consequences of CNS lesions, including cerebral palsy (CP), are formed more reliably often in children who had low activity levels of these enzymes, primarily SDH, during the early neonatal period.

In the case of complicated pregnancy and labor, a positive role of cesarean section in reducing the frequency of severe consequences of perinatal lesions of the CNS, including cerebral palsy, in premature children has been demonstrated.

The development of lactic acidosis during the early neonatal period is a risk factor for an unfavorable neurological outcome in children up to 1.5 years of age.

Practical Significance

The obtained data make it possible to assess the prognosis and severity of the development of perinatal lesions of the CNS during the early neonatal period and severe neurological pathology up to 1.5 years of age in premature children depending on the method of delivery — natural birth or cesarean section — taking into account birth weight, gestational age, and the presence of such maternal complications as gestosis, breech and footling fetal presentation. The results of the conducted study are of important significance for the practical perinatologist in choosing the optimal method of delivery in the interests of the fetus during premature complicated births, taking into account possible near-term and long-term adverse consequences for the child. The results obtained substantiate the necessity of focusing attention on improving the quality of perinatal services in order to reduce morbidity and mortality among premature children.

The work was carried out at the Moscow Research Institute of Pediatrics and Pediatric Surgery of the Ministry of Health of the Russian Federation (director — Doctor of Medical Sciences, Professor A.D. Tsaregordtsev).

The solution of the set tasks was carried out in the Department of Physiology and Pathology of Newborns (head — Honored Physician of the Russian Federation, Doctor of Medical Sciences, Professor G.M. Dementyeva). Clinical observations were conducted at Maternity Hospital No. 15 of Moscow (chief physician — Candidate of Medical Sciences V.P. Kuznetsov). Biochemical studies were performed at the Research Laboratory of General Pathology (head — Doctor of Medical Sciences, Professor V.S. Sukhorukie).

The author expresses deep gratitude for practical and consultative assistance in the performance of the work to the head of the Department of Physiology and Pathology of Newborns, Doctor of Medical Sciences, Professor G.M. Dementyeva, and to the research fellow of the Research Laboratory of General Pathology, Candidate of Medical Sciences N.V. Kleymenova.

Validation and Implementation of Results

The results of the research have been implemented in the clinical practice of Maternity Hospital No. 15 of Moscow.

The materials of the dissertation were presented at the Second Russian Congress "Modern Technologies in Pediatrics and Pediatric Surgery" (Moscow, 2003).

Three printed works have been published on the topic of the dissertation.