Maternal and fetal cardiovascular dynamics were studied immediately after moderate short-term maternal exercise in 28 healthy nulliparous subjects at between 34 and 38 weeks gestation who were randomly assigned to an exercise group (n = 14) or a control group (n = 14). At the end of the study, data from 11 exercise and 12 control subjects were available for analysis. A significant rise in maternal heart rate and systolic and diastolic blood pressure during exercise was observed. Mean blood flow velocity in the fetal descending aorta as measured by pulsed Doppler ultrasound and fetal heart rate did not show any significant changes. These data indicate that there are no cardiovascular signs of fetal stress immediately after moderate short-term maternal exercise.