Effects of Prenatal Yoga on Women's Stress and Immune Function Across Pregnancy

Monday, 30 October 2017

Jen-Jiuan Liaw, PhD, RN
School of Nursing, National Defense Medical Center, Taipei, Taiwan

Objective: During pregnancy, women undergo bio-physio-psycho-social changes that may cause stress. The effects of prenatal yoga on biological indicators have not been widely studied. At present, none of these studies measured the effect of yoga on pregnant women’s IgA levels. Thus, the study compared changes in stress and immunity salivary biomarkers from 16 to 36 weeks’ gestation between women receiving prenatal yoga and those receiving routine prenatal care.

Design: For this longitudinal, prospective, randomized controlled trial, we recruited 94 healthy pregnant women at 16 weeks’ gestation through convenience sampling from a prenatal clinic in Taipei. Participants were randomly assigned to intervention (n=48) or control (n=46) groups using Clinstat block randomization. From 16 to 36 weeks’ GA, participants in the control group received only routine prenatal care, and those in the intervention group received routine prenatal care plus the yoga intervention. This study followed the CONSORT guidelines.

Intervention: The 20-week intervention comprised two weekly 70-minute yoga sessions led by a midwife certified as a yoga instructor; the control group received only routine prenatal care.

Main outcome measures: In both groups, participants’ salivary cortisol and immunoglobulin A levels were collected before and after yoga every 4 weeks from 16 to 36 weeks’ gestation.

Results: The intervention group had lower salivary cortisol (p<0.001) and higher immunoglobulin A (p<0.001) levels immediately after yoga than the control group. Specifically, the intervention group had significantly higher long-term salivary immunoglobulin A levels than the control group (p=0.018), and infants born to women in the intervention group weighed more than those born to the control group (p<0.001).

Conclusion: Prenatal yoga significantly reduced pregnant women’s stress and enhanced their immune function. Clinicians should learn the mechanisms of yoga and its effects on pregnant women. Our findings can guide clinicians to help pregnant women alleviate their stress and enhance their immune function.