Objective
To evaluate fetal responses to strenuous exercise in physically active and inactive women.
Study Design
45 healthy women (15 Non-Exercisers, 15 Regularly Active, 15 Highly Active) underwent a peak treadmill test at 28-0/7 to 32-6/7 weeks. Fetal well-being [umbilical artery Dopplers, fetal heart tracing/rate, biophysical profile (BPP)] was evaluated pre and post-exercise. Uterine artery Dopplers were also obtained.
Results
Umbilical and uterine artery Doppler indices were similar among activity groups and did not change with exercise (P>.05). BPP and fetal heart tracings were reassuring in all groups. However, subgroup analyses showed transient post-exercise fetal heart rate decelerations and elevated umbilical and uterine artery Doppler indices in 5 Highly Active women. Following this, BPP and fetal heart tracings were reassuring.
Conclusions
Overall fetal well-being is reassuring after short-duration, strenuous exercise in both active and inactive pregnant women. 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. However, potential impact on neonatal outcomes is unknown.