Fetal heart function in response to short-term maternal exercise.

Fetal cardiac reactions to maternal exercise were studied in the fetuses of 22 healthy pregnant women between 18 and 36 weeks of gestation. Before and 5 min after a bicycle ergometer load test of 75 W each fetus was studied with M-mode echocardiography. Fetal cardiac dimensions, ventricular ejection times and heart rate were recorded and indices of left ventricular heart function (fractional shortening, mean velocity of fractional shortening, stroke volume and cardiac output) were calculated. While median maternal heart rate acceleration reached 68% of expected maximum heart rate, no significant alterations in fetal heart rate, fetal cardiac dimensions or fetal ventricular function were observed. The results indicate that short-term moderate maternal exercise can be performed without fetal cardiac distress.