Synchronous Effects of Light and Noise Prenatal Stress on Birth Weight among Rat Neonates

Early life stress (including the ones during fetal development) has been hypothesized to predispose individuals to several illnesses and psychiatric disorders later in adulthood. The aim of this study was to evaluate the synchronous effects of light and noise prenatal stress on birth weight among rat neonates

In this case-control study, pregnant Sprague-Dawley rats were divided into two groups of under-stress and control. Stress was imposed to the under-stress pregnant females from the 15th day of pregnancy until delivery. Pregnant rats were acutely stressed for 45 minutes three times in day with noise and light. Postpartum neonates in under-stress and control groups were weighted. The weight of adrenal gland and ACTH levels were evaluated in the mothers at postpartum to determine the activity of hypothalamic-pituitary-adrenal. Data were analyzed using t-test.

Results showed a significant difference between the weights of neonatal in two groups (p<0.05). Compared to that of control group, prenatal stress led to a reduced birth weight in under-stress group of neonatal. Induced stresses associated with increased hypothalamus- pituitary-adrenal axis activity in mothers, reflected by higher ACTH level and also increase in weight of adrenal glands in under-stress rats compared to control group.

These findings indicate that the noise and light stress during pregnancy can deregulate neuroendocrine system of mothers and can causes the low birth weight of the neonates.