Abstract

This study was designed to test the hypothesis that continuation of a regular running and/or aerobics program during late pregnancy at or above 50 of preconceptional levels limits fetal growth. Accordingly, detailed neonatal morphometric data were gathered in the offspring of two groups: 77 well-conditioned recreational runners and aerobic dancers who were delivered at term after continuing their exercise regimen at or above 50 of the preconceptional level throughout pregnancy and 55 matched controls. Daily exercise performance was quantitated before conception and throughout pregnancy. Significant reductions in birth weight (-310 gm), birth weight percentile (-20), ponderal index (-0.24), its percentile (-30), and the fetoplacental weight ratio (-0.7) were seen in the offspring of the exercise group whereas crown-heel length (51.4 cm) and head circumference (35.0) were similar in the two groups. Reductions in two-site skin-fold thickness (-1.5 mm), skin-fold percentile (-30), calculated percent body fat (-5.0), and fat mass (-220 gm) in the offspring of the exercise group confirmed the asymmetric pattern of growth restriction and indicated that approximately 70 of the difference in birth weight could be explained by the difference in neonatal fat mass. In runners, the relative level of exercise performance in the last 5 months of pregnancy explained 40 of the variability in birth weight over an 1100 gm birth weight range. Verf.-Referat (gekuerzt)