Reduced uterine blood flow and fetal hypoxemia with acute maternal stress: experimental observation in the pregnant baboon.

The effects of maternal hyperexcitability on the fetus were studied in 17 baboons. In the period of agitation, induced by stressful stimulus such as exposure to bright light or by clamping of the toe, the mother exhibited an increase in arterial blood pressure and, in some instances, arrhythmia. These changes were accompanied by an increased uterine activity and reduced uterine blood flow, and resulted in a decrease in heart rate and arterial oxygenation in all fetuses. Fetal recovery was prompt after maternal agitation was terminated, either by removal of the stimulus or by sedation with pentobarbital or nitrous oxide. This sedation also prevented a decrease in uterine blood flow when stress was repeated.