Stress in pregnancy: A new Wistar rat model for human preeclampsia

OBJECTIVE: Our study evaluated the effects of chronic and/or acute stress on pregnant and nonpregnant female rats. STUDY DESIGN: The rats were exposed to the sonic stimulus associated with overpopulation between days 7 and 14 of pregnancy. The rats were immobilized 2 days before the vascular reactivity experiments. RESULTS: In 14-day pregnant rats, chronic stress led to lower weight, increased adrenal weight, lower endothelium-derived relaxing factor release, and lower fetal weight. In 20-day pregnant rats, chronic stress caused decreased weight gain, higher blood pressure, increased vasomotility and proteinuria, lower endothelium-derived relaxing factor release, and lower fetal weight. In the 20-day pregnant group, the higher adrenal weight resulted in higher blood pressure, lower vascular relaxation, and lower average fetal weight. A greater number of fetuses had higher adrenal weight, higher blood pressure, and lower vascular relaxation. CONCLUSION: The alterations found in the rats were similar to those that occur in human preeclampsia. Therefore, we propose a new animal model for human preeclampsia. (Am J Obstet Gynecol 2002;186:544-50.)