A recent study, published in the Journal of Obstetrics and Gynaecology Research, investigated the changes in daily variation in the autonomic nervous system during pregnancy on account of maternity yoga and assessed how maternal yoga affected stress and sleep. Pregnant women attending maternity yoga classes from 20 to 23 weeks’ gestation formed the yoga group (n=38), and a matched control group (n=53) 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 assessed at 20–23 weeks’ gestation, 28–31 weeks’ gestation and 36–40 weeks’ gestation.

At 28–31 weeks’ gestation, heart rate variability during night and late‐night periods was significantly higher in the yoga group as compared to 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 showed significant reduction immediately after practicing yoga during all evaluation periods in the yoga group. Additionally, night‐time sleep duration was significantly longer in the yoga group.

The study thus suggested that practicing yoga activated the parasympathetic nervous system during the third trimester, consolidating sleep during night and decreasing α‐amylase levels, thus pointing to reduced stress.