Aerobic exercise during pregnancy influences infant heart rate variability at one month of age

Background: Previously, we reported that regular maternal aerobic exercise during pregnancy was associated with lower fetal heart rate (HR) and higher heart rate variability (HRV) at 36 weeks gestation. We now report the effect of maternal exercise on infant HR and HRV in subjects who remained active in the study at the one-month follow up visit. Aims: We aimed to determine whether differences in fetal cardiac autonomic control related to maternal physical activity were an in utero phenomenon or would persist 1 month after birth. Study design: Magnetocardiograms (MCGs) of infants born to regularly exercising (>= 30 min of aerobic activity, 3 times per week; N = 16) and non-exercising (N = 27) pregnant women were recorded using a fetal biomagnetometer. Normal R-peaks were marked to derive infant HR and HRV in time and frequency domains, including the root mean square of successive differences (RMSSD), the standard deviation of normal-to-normal interbeat intervals (SDNN), and power in the low frequency (LF) and high frequency (HF) bands. Group differences were examined with Student's t-tests. Results: Infants born to exercising women had significantly higher RMSSD (P = 0.010), LF power (P = 0.002), and HF power (P = 0.004) than those born to women who did not engage in regular physical activity while pregnant. Conclusion: Infants born to women who participated in regular physical activity during pregnancy continued to have higher HRV in the infant period. This suggests that the developing cardiac autonomic nervous system is sensitive to the effects of maternal physical activity and is a target for fetal programming. (C) 2013 Elsevier Ireland Ltd. All rights reserved.