Maternal activity in relation to birth size in rural India. The Pune Maternal Nutrition Study

Objective: To describe the relationship of the mother's physical activity to the birth size of her baby in a rural Indian population.Design: Prospective observational study.Setting: Six villages near Pune, Maharashtra, India.Subjects: A total of 797 women were studied after excluding abortions and termination of pregnancies (112), foetal anomalies (8), multiple pregnancies (3), incomplete pre-pregnancy anthropometry (14) and pregnancies detected later than 21 weeks of gestation (168).Method: An activity questionnaire was developed after focus group discussions and incorporated community-specific activities. It was validated against an observer-maintained diary. Activity scores were derived using published data on energy costs to weight the contributions of various activities. It was then administered to assess physical activity at 18 (±2) and 28 (±2) weeks of gestation.Outcome measures: Birth outcome, maternal weight gain and neonatal anthropometry.Results: The activity questionnaire was used to classify women into light, moderate and heavy activity categories. Maternal activity did not influence the incidence of prematurity or stillbirth, or the duration of gestation. It was inversely related to maternal weight gain up to 28 weeks of gestation (P=0.002). Higher maternal activity in early, as well as mid gestation, was associated with lower mean birth weight (P=0.05 and 0.02, respectively ), and smaller neonatal head circumference (P=0.005 and 0.009) and mid-arm circumference (P=0.03 and 0.01) after adjusting for the effect of major confounding factors.Conclusions: The Findings suggest that excessive maternal activity during pregnancy is associated with smaller foetal size in rural India, The approach described for developing an activity questionnaire has potential for adoption in other settings.