Associations between second-trimester maternal physical activity and neonatal body composition: findings from the...

The impact of maternal physical activity on infant body composition remains understudied. This study aimed to investigate the association between maternal activity levels during pregnancy and infant body fat percentage, utilising data from the Western Australian ORIGINS birth cohort. A total of 323 pregnant women and their male (148) and female (175) infants born during 2016-2024 were included in the analysis. Maternal physical activity was measured with the International Physical Activity Questionnaire (IPAQ) and the Godin Leisure-Time Exercise (Godin) questionnaire during the second trimester. Infant body composition was measured within 7 d of birth using infant air displacement plethysmography (PEA POD). Associations were calculated using linear regression models adjusted for confounders. A significant difference in neonatal body fat percentage was observed between sexes, with males averaging 11.7% and females 13.0% (p = 0.005). Analyses of maternal physical activity during the second trimester demonstrated sex-specific effects on infant body fat percentage. High maternal activity levels were associated with lower body fat percentage for female infants (IPAQ: -3.23, 95% CI: -5.22, -1.23 and Godin: -1.73, 95% CI: -3.26, -0.22), while for males, no association was observed. These results suggest that tailored prenatal care strategies that promote exercise and a healthy diet would be beneficial to pregnant women. Further research is needed to explore additional factors that could influence infant body fat percentage, which in turn could enhance prenatal care recommendations.