Pregnancy in adolescent rats, growth and neurodevelopment in their offspring.

Pregnancy, lactation and the relationship between mother and their offspring in adolescence was studied in terms of pups neurosomatic development. The frequency of conception and birth rate were reduced in adolescent dams. Their body weight gain was accelerated during the first two weeks of pregnancy, while a significant delay occurred in the third week. At birth, plasma corticosterone level in the neonates was increased. Adolescent dams ingested less food during the first week of gestation. Following that, till the second week of lactation, the food consumption was equal to that of control group. Although adolescent pups were heavier at birth, the reduction of their number and of their body weight occurred during lactation. Judging by appearance of grasping, righting, placing and of negative geotaxis reflexes, the delay in their neurological maturation was also present. The reason for the growth and neurodevelopmental delay during lactation is probably the result of malnutrition and stress of disturbed mother - infant relationship in adolescent litters, which lasted at least during the two postnatal weeks. It was indicated by the resting plasma corticosterone levels during the first two postnatal weeks. This finding suggests that the pregnancy in adolescent rats induces delay in physical and neurological development, as well as in the increased rate of postnatal mortality of their offspring.