Effects of maternity yoga on the autonomic nervous system during pregnancy.

AIM: To elucidate the changes in the daily variation seen in the autonomic nervous system during pregnancy brought about by maternity yoga and to evaluate how maternal yoga affects stress and sleep.

METHODS: A prospective, longitudinal study was conducted between January 2013 and December 2014. Pregnant women who were attending maternity yoga classes at Palmore Hospital between 20 and 23 weeks' gestation were enrolled as the yoga group, and a matched control group was also enrolled. Study participants completed questionnaires, including a perceived stress scale and sleep logs, during their second and third trimesters. Heart rate variability and salivary α-amylase levels were evaluated as stress indices at 20-23 weeks' gestation, 28-31 weeks' gestation and 36-40 weeks' gestation.

RESULTS: A total of 38 women were in the yoga group, with 53 in the control group. At 28-31 weeks' gestation, heart rate variability during night and late-night periods was significantly higher in the yoga group than in the control group. At 36-40 weeks' gestation, variability between the morning, afternoon and late night was significantly higher in the yoga group. Salivary α-amylase levels decreased significantly immediately after practicing yoga during all evaluation periods in the yoga group. Night-time sleep duration was significantly longer in the yoga group.

CONCLUSION: Our results suggest that practicing yoga activates the parasympathetic nervous system during the third trimester of pregnancy, consolidating sleep during the night and decreasing α-amylase levels, which indicates reduced stress.