Maternal recreational physical activity is associated with plasma leptin concentrations in early pregnancy.

BACKGROUND

A limited amount of literature suggests that plasma leptin concentrations are reduced with habitual physical activity in men and non-pregnant women. We investigated the relationship between maternal physical activity and plasma leptin during early pregnancy.

METHODS

The study population included 879 normotensive, non-diabetic pregnant women who reported physical activity type, frequency, and duration in early pregnancy. Plasma leptin, measured in blood samples collected <16 weeks gestation, were determined using enzyme immunoassays. Weekly duration (h/week) and energy expended on recreational physical activity [metabolic equivalent score (MET)-h/week] were categorized by tertiles among active women. Physical activity intensity was categorized as none, moderate (<6 MET) and vigorous (> or =6 MET). Differences in leptin concentrations across categories were estimated using linear regression procedures.

RESULTS

Mean leptin was 5.8 ng/ml lower among active versus inactive women (P=0.001). Mean leptin was lower among women in the highest levels (>12.8 h/week) of time performing physical activity (-8.1 ng/ml, P<0.001) and energy expenditure (>70.4 MET-h/week) (-8.3 ng/ml, P=0.001) compared with inactive women. Leptin was inversely associated with the intensity of physical activity.

CONCLUSIONS

Our findings are consistent with other reports suggesting an independent inverse relationship between habitual physical activity and leptin concentrations. Our findings extend the literature to include pregnant women.