Physical activity during pregnancy is associated with reduced fasting insulin – the Pilot Pregnancy and Active Living Study

Objective. To examine the relationship between physical activity during pregnancy and fasting plasma insulin measured in the second trimester.Study design and methods. We conducted a pilot prospective cohort study of 69 overweight or obese women who were enrolled before 20 weeks of gestation at an obstetric clinic in Columbia, South Carolina in 2006–2007. At 24–28 weeks of gestation, fasting blood samples were collected and physical activity from the 3 months prior to the visit was assessed using a validated Pregnancy Physical Activity Questionnaire.Results. Total energy expenditure (EE) in this population was attributable to sedentary activities (24.4%) and to physical activities of different intensities (light: 44.8%, moderate: 30.2%, and vigorous: 0.6%). By type, total EE mainly came from household/caregiving activities (58.9%) with a small proportion from exercise (3.8%). After adjusting for confounders, the mean fasting insulin values across the quartiles of total EE (least to most) were 17.3, 13.0, 12.1, and 9.6 uIU/ml (P for trend = 0.01).Conclusion. Our findings suggest that increased total physical activity is associated with reduced fasting insulin levels in overweight or obese pregnant women.