Leisure-Time Physical Activity During Pregnancy and Offspring Size at 18 to 24 Months

Background: Leisure-time physical activity (LTPA) during pregnancy has maternal benefits, but effects on offspring have not often been considered. This study aimed to determine associations among trimester-specific LTPA during pregnancy and toddler size. Methods: Women (n = 300) were recruited while pregnant in 2006. At follow-up (2008), women reported demographics; recalled type, duration, and frequency of trimester-specific LTPA (MET.min/wk); and rated their toddler's current LTPA level (more, same, or less than others their age). A subset (n = 23) volunteered to have maternal and toddler height, weight, and body fat measured. Maternal body mass index (BMI) and toddler weight-for-height z-scores (WHZ) were calculated. Results: Median toddler WHZ was 0.6 (range -0.5 to 2.9). In Spearman correlations, third trimester LTPA was marginally associated with lower toddler weight (r(s) = 0.39, P=.06) and WHZ (r(s) = 0.40, P=.06), but no other measures of maternal LTPA and toddler body size were related. Birth weight z-score was positively associated with toddler weight (r(s) = 0.51, P=.01) but negatively associated with percent body fat (r(s) = -0.46, P=.03). Measures of maternal size were unassociated with toddler size. Conclusions: These results provide preliminary support for LTPA during late pregnancy to have a lasting effect on offspring size.