From Big Medical Encyclopedia

PERINATAL PERIOD (grech, peri around, about + armor. natus birth; synonym okodorodovy period) — the period beginning of 28 weeks of pregnancy, including the period of childbirth and the first 7 days of life of the newborn.

Duration of Pct is various and depends on a number of the factors defining approach of childbirth (see. Perenashivany pregnancies , Premature births ). E.g., at the child born in 28 weeks of pregnancy, the Pct consists of the period of childbirth and the first seven days of life. The greatest Pct on duration is marked at a perenashivaniye of pregnancy.

The pct is the major stage causing physical, psychological and intellectual development of the child.

In Pct there is a maturing of the functions necessary for independent existence of an organism of the newborn. According to P. K. Anokhin (1966) the fruit by 28th week has an association in functional systems (in system of digestion, breath, etc.) separate local reactions (see. Fruit ).

Probability of serious neurologic and somatic violations in Pct considerably big, than during other periods of life. During the period from 28 to 40th week of pregnancy there is a further preparation of a fruit for childbirth and for post-natal life. Functional systems of a fruit by the time of childbirth though are imperfect, but are sufficient for ensuring its viability during childbirth when the fruit is affected by the expelling forces of a uterus and a lack of oxygen. In time fiziol, childbirth the expressed activation of gipofizarnonadpochechnikovy system of mother and closed glands of a fruit is observed that is shown in strengthening of total corticosteroids and growth hormones, especially expressed at a hypoxia of a fruit.

Childbirth (see) make essential impact on a condition of functional systems of a fruit and are their peculiar testing biol, reliability. The nature of childbirth and a way of delivery define degree and the nature of reactions of adaptation fruit (see) and newborn (see). At childbirth in natural patrimonial ways consecutive activation of functions of bark of adrenal glands, a thyroid gland and hypophysis is observed. At the newborns taken by Cesarean section simultaneous activation of functions of bark of adrenal glands and a thyroid gland, the strengthened emission in a peripheral bed of erythrocytes and leukocytes the first minutes after the birth is observed. Bystry reaction of endocrine system and blood after Cesarean section compensates yet not developing adaptation of c. N of page. In cases when the fruit is not affected by physiological childbirth (at Cesarean section prior to patrimonial activity), timely inclusion of system of breath is not observed; its formation happens without tension of function of external respiration therefore it becomes adequate only by the end of the first hour of life. When the fruit at the time of delivery experiences especially intensive influences (at bystry childbirth, an acute short-term hypoxia), adaptatsionnokompensatorny reactions of system of breath, a hemopoiesis and endocrine system are expressed most brightly. The slight and quickly operating hypoxia promote more prematurity of reactions of adaptation of a fruit. The heavy and long hypoxia leads to oppression of reactions of adaptation. Primary adaptation to the environment of the vital systems at the full-term newborn comes to the end in the first 7 days of life. At premature children (see) processes of adaptation proceed more slowly: they that are less perfect, than the maturity of a fruit by the time of childbirth is less. At children of the low weight (weight) at the birth (1000 — 1500) the period of adaptation is extended to 3 — 4 weeks.

Pathology of Pct is connected with the adverse factors influencing during the period of pre-natal fetation since 28 weeks of pregnancy, pathology of childbirth and also with adverse effects of the environment in the first 7 days of life (see. Antenatal pathology , Perinatal pathology ).

Bibliography: Bagramyan E. R. Endocrine systems of adaptation of a fruit and newborn, Akush, and ginek., No. 9, page 9, 1979; Clinical aspects of processes of adaptation at newborns, under the editorship of E. Ch. Novikova and G. P. Polyakova, M., 1974; Sketches on physiology of a fruit and the newborn, under the editorship of V. I. Bo-dyazhina, page 9, 100, M., 1966; Perinatal medicine, ed. by E. Kerpel-Fronius a. lake, Budapest, 1978.

I. P. Yelizarova.