[The effect of water deprivation on the mother-fetus system at different stages of pregnancy in rats].

Female Wistar rats were exposed to stress (water deprivation) during 3 days starting from the 8th, 14th or 19th day of pregnancy. In all cases serious changes in the mother's organism were observed and they were manifested in the essential delay of body mass increment. The main indexes of reproductive function (the number of alive new-born rats, relationship between males and females in broods) did not change. The signs of lagging behind in development were revealed for experimental groups of new-born rats (less body mass, delay of bone formation) and they were the most pronounced in the group exposed to stress at the 14-17th day of pregnancy. In postnatal period no essential differences between experimental groups and control in terms of teeth appearance, hearing onset, as well as in the indexes of physical endurance were observed. Behavioral reactions of progeny in the "open field" appeared to be changed only for the generation of female rats exposed to stress in the second period of pregnancy and were different on the exposures as of the 14-17th and 19th-22nd day of pregnancy. The results obtained have been discussed in the context of views about critical periods of development.