RESUMO
Abstract Purpose: To evaluate the effects of oxidative stress in pregnant rats submitted to acute and chronic stress, relating to alterations in the uterus, placenta and fetus. Methods: Twenty-four female Wistar albino (Rattus norvegicus), were divided into four groups, for induction of oxidative stress the animals were submitted to cold and physical immobilization. Plasma fasting glucose and MDA were determined in all groups and the fetuses and placentas were measured. Results: There were no statistical differences in the levels of malonic dialdehyde (MDA), however the averages of chronic stress group were higher compared to control groups, which could explain the observed adverse effects; there was no correlation between puppies' size, the weight of the placenta and MDA values. Conclusions: Chronic stress causes adverse effects, when compared to control groups; chronic stress group had fetuses, placentas and number of puppies, significantly lower compared to other groups. The rats exposed to chronic stress, also presented a higher frequency of fetal resorption.