Effects of Physical Activity During Pregnancy on Maternal and Fetal Health Outcomes

Abstract

IntroductionPhysical activity during pregnancy and its effects on fetal fat accrual and lipids has not been deeply explored. The purpose of this study was to further investigate how fitness during pregnancy relates to neonatal adiposity.Methods30 mothers were surveyed using the Pregnancy Physical Activity Questionnaire (PPAQ) at early pregnancy (EP; 12‐16 weeks), and of these 27 completed the study at late pregnancy (LP; 34‐36 weeks). Mothers were analyzed by sedentary, light, moderate, and vigorous activities, involvement in caregiving, occupations, and exercise. Mothers’ body composition (% fat and fat free mass) assessed by air densitometry (BOD POD), and BMI, were tracked throughout pregnancy. Infant adiposity (% fat via air densitometry/PEA POD) was measured within 48 hours of birth. Umbilical venous (UV) lipid levels were measured in the clinical pathology lab by standard methodology. Associations between maternal physical activity and infant outcomes were analyzed using non‐parametric Spearman correlation.ResultsEP fitness scores were positively correlated with parity (P=0.0047). EP overall scores were positively correlated with higher first trimester maternal BMI (P=0.0205). EP fitness scores were negatively correlated with infant % fat free mass (P=0.0407), and showed no significant correlation with any other infant factors post birth. LP PPAQ scores were negatively correlated with infant % fat free mass (P=0.0180); and positively correlated to infant % fat (P=0.0230). LP fitness scores, unlike EP, were negatively correlated with UV LDL, non‐HDL, and cholesterol readings (P=0.0172, P=0.0347, and P=0.0087, respectively). Infants of mothers who decreased in fitness between EP and LP had trends of higher levels of UV HDL, LDL, and non‐LDL compared to infants of mothers who had increased fitness.ConclusionUnexpectedly, higher maternal fitness levels correlated with higher maternal BMI and infant adiposity, potentially due to skewness in the PPAQ towards questions involving household or caregiving activity. Indeed, higher fitness scores were associated with parity. As postpartum weight retention is a risk factor for obesity, this may also explain the positive correlation between fitness and infant adiposity, potentially mediated by high maternal BMI. As the change in maternal fitness from EP to LP is correlated with UV lipids, our findings suggest that modifications of maternal physical activity during pregnancy may impact lipid transfer in utero. Future studies should investigate the effect of maternal fitness on placental function.