Maternal Physical Activity and Neonatal Cord Blood pH: Findings from the Born in Bradford Pregnancy Cohort

Objective: Evidence suggests that physical activity whilst pregnant is beneficially associated with maternal cardiometabolic health and perinatal outcomes. It is unknown if benefits extend to objective markers of the neonate condition at birth. This study investigated associations of maternal pregnancy physical activity with cord blood pH. Methods: Cord blood pH was measured when clinically indicated in a subgroup of Born in Bradford birth cohort participants (n = 1,467). Pregnant women were grouped into one of four activity categories (inactive/somewhat active/moderately active/active) based on their self-reported physical activity at 26–28 weeks gestation. Linear regression was used to calculate adjusted mean differences in cord blood pH, and Poisson regression was used to quantify relative risks for moderate cord blood acidaemia (pH Results: More than half of pregnant women (52.0%) were inactive, one-fifth were somewhat active (21.7%), fewer were moderately active (14.6%) and active (11.7%), respectively. Pregnancy physical activity was favourably associated with higher cord blood pH. Compared to neonates of inactive women, there was some evidence that neonates of women who were at least somewhat active in pregnancy had lower relative risk of moderate cord blood acidaemia (for arterial blood: relative risk = 0.70 (95% confidence interval 0.48–1.03)). Conclusions: Modest volumes of mid-pregnancy maternal physical activity do not appear to adversely influence cord blood pH and may enhance the neonate condition at birth.