Fetal well-being generally fine after strenuous exercise

(HealthDay)—In general, fetal well-being is fine after strenuous exercise in both active and inactive pregnant women, according to a study published in the September issue of the American Journal of Obstetrics & Gynecology.

Linda M. Szymanski, M.D., Ph.D., and Andrew J. Satin, M.D., from the Johns Hopkins University School of Medicine in Baltimore, analyzed fetal well-being in 45 healthy women (15 nonexercisers, 15 regularly active, and 15 highly active). Participants underwent a peak treadmill test at 28 weeks' to 32 weeks 6 days' gestation. Before and after exercise, fetal well-being was measured using umbilical artery Doppler indices, fetal heart tracing/rate, and biophysical profile (BPP).

The researchers found that, among the activity groups, umbilical and uterine artery Doppler indices were similar and there was no change with exercise. In all groups, BPP and fetal heart tracings were reassuring. However, in five highly-active women, there were transient fetal heart rate decelerations after exercise and elevated umbilical and uterine artery Doppler indices. Following this, BPP and fetal heart tracings returned to reassuring levels.

"Overall fetal well-being is reassuring after short-duration, strenuous exercise in both active and inactive pregnant women," the authors write. "A subset of highly-active women experienced transient fetal heart rate decelerations and Doppler changes immediately after exercise. Athletes may push beyond a threshold intensity at which fetal well-being may be compromised."