Objective: To test the hypothesis that continuing regular, vigorous, sustained exercise throughout pregnancy adversely affects morphometric and neurodevelopmental outcome in offspring at 5 years of age.
Study design: The offspring of 20 women who exercised were compared with those of 20 physically active control subjects. The women and their offspring were matched for multiple prenatal and postnatal variables known to influence outcome. All women were enrolled before the index pregnancy, monitored throughout, and had clinically normal antenatal, intrapartum, and postnatal courses. Morphometric measures were obtained at birth and at 5 years of age by a single, trained observer. Neurodevelopment was assessed by developmental psychologists masked to maternal exercise status. Data were analyzed with an unpaired Student t test.
Results: At birth, head circumference and length were similar, but the offspring of the exercising women weighed less (3.40 +/- 0.80 vs 3.64 +/- 0.70 kg) and had less fat (10.5% +/- 0.9% vs 15.1% +/- 0.6%). At 5 years of age, head circumference and height were similar, but the offspring of the women who exercised weighed less (18.0 +/- 0.5 vs 19.5 +/- 0.6 kg) and had a lower sum (sigma) of five site skinfolds (37 +/- 1 vs 44 +/- 2 mm). Motor, integrative, and academic readiness skills were similar. However, the exercise offspring performed significantly better on the Wechsler scales (125 +/- 2 vs 116 +/- 3) and tests of oral language skills (119 +/- 2 vs 109 +/- 3).
Conclusions: These data refute the hypothesis and suggest that exercise during pregnancy reduces the subcutaneous fat mass of the offspring.