To study the efficacy of yoga on the outcome of complicated pregnancy, 121 women attending antenatal clinic at Gunasheela Surgical and Maternity Hospital (GSMH) in Bangalore, India, were enrolled between 18-20 weeks of pregnancy in a prospective, matched, observational study. Sixty-eight women were in the yoga group and 53 women in the control group. Women were matched for age, gravida and Doppler velocimetry scores of umbilical and uterine arteries. Yoga practices including physical postures, breathing and meditation were practised by the yoga group, one hour daily, from the date of entry into the study until delivery. The control group walked half an hour twice a day during the study period. Compliance in both the groups was ensured. In babies the birth-weight is significantly higher (P < 0.018) in the Yoga group (2.78 +/- 0.52 kg), compared to the control group (2.55 +/- 0.52 kg). Occurrence of complications of pregnancy (pregnancy-induced hypertension, intrauterine growth retardation, pre-term delivery) shows lower trends in yoga group.