Beginning regular exercise in early pregnancy: Effect on fetoplacental growth

OBJECTIVE: Our purpose was to test the null hypothesis that beginning regul ar, moderate-intensity exercise in early pregnancy has no effect on fetopla cental growth. STUDY DESIGN: Forty-six women who did not exercise regularly were: randomly assigned at 8 weeks either to no exercise (n = 24) or to weight-bearing ex ercise (n = 22) 3 to 5 times a week for the remainder of pregnancy. Outcome variables included antenatal placental growth rate and neonatal and placen tal morphometric measurements. RESULTS: The offspring of the exercising women were significantly heavier ( corrected birth weight: 3.75 +/- 0.08 Mg vs 3.49 +/- 0.07 Mg) and longer (5 1.8 +/- 0.3 cm vs 50.6 +/- 0.3 cm) than those born to control women. The di fference in birth weight was the result of an increase in both lean body ma ss and fat mass. In addition, midtrimester placental growth rate was faster (26 +/- 2 cm(3)/wk vs 21 +/- 1 cm(3)/wk) and morphometric indexes of place ntal function were greater in the exercise group. There were no significant differences in neonatal percentage body fat, head circumference, ponderal index, or maternal weight gain. CONCLUSIONS: These data indicate that beginning a moderate regimen of weigh t-bearing exercise in early pregnancy enhances fetoplacental growth.