Women’s Health
Physical activity during pregnancy and gestational weight gain among nulliparous women Tingju Hsu* Tingju Hsu Tsung Yu
Introduction: Excessive gestational weight gain (GWG) is associated with adverse pregnancy outcomes and longer-term obesity in both mother and child. Physical activity (PA) may mitigate these risks, yet optimal timing and quantity remain unclear. Method: We analyzed the association between PA and excess GWG among 5724 participants from the Nulliparous Pregnancy Outcomes Study: Monitoring Mothers-to-be (nuMoM2b). Participants reported their PA at 3 study visits: between 6–13 (visit 1), 16–21(visit 2), and 22–29 weeks (visit 3). Weekly PA was summed into metabolic equivalents (MET) and categorized with 3 levels: less than 7.5, 7.5 to less than 21, and 21 or above MET hours. Weights were measured at each visit. Pre-pregnancy weight and weight prior to delivery were also available. Excessive GWG was defined as above 75th percentile on gestational age-specific charts based on participants’ pre-pregnancy BMI. We used logistic regression models to evaluate associations between PA and excessive GWG at visit 2 and prior to delivery. Results: There was no difference in the odds of excessive GWG among participants with 3 PA levels in early pregnancy at visit 2. On the other hand, the participants with weekly PA of 21 MET hours or above had a significantly lower risk of excessive GWG (OR=0.74 with 95% CI [0.61,0.90]) compared to participants with weekly PA <7.5 MET hours during later pregnancy prior to delivery. The OR was attenuated and became statistically insignificant but remained in the same direction (adjusted OR=0.83 with 95% CI [0.68, 1.02]) after adjusting for age, race-ethnicity, socio-economic status, alcohol and tobacco consumption, dietary intake and comorbidities. No significant difference in excessive GWG was found between participants with <7.5 and 7.5 to <21 weekly MET hours. Conclusions: These findings underscore the nuanced impact of prenatal PA timing and quantity and support the promotion of PA throughout pregnancy to minimize excessive GWG at delivery.