Physical Activity before and during Pregnancy in Relation to Delivery, Neonatal, and Child Health Outcomes: A Meta-Analysis of Observational Studies with Meta-Regression.

Background: An increasing number of observational studies suggest that physical activity (PA) before or during pregnancy may reduce the risks of adverse delivery, neonatal, and child health outcomes, but the results remain conflicted and inconclusive. Many pregnant women fail to follow PA guidelines, suggesting that there must be a synthesis of real-world evidence.

Objective: To examine the influence of PA before and during pregnancy on delivery, neonatal, and child health outcomes.

Methods: Ten electronic databases have been searched until December 17, 2024. All types of observational studies were included, except for case studies and reviews, as long as they had data on women before or during pregnancy, looked at physical activity (either measured or reported), compared it to low or no physical activity, and examined outcomes related to birth (like preterm birth, low birth weight, cesarean section, small-for-gestational-age, larger-for-gestational-age, macrosomia) and child health (like BMI-z score, overweight, body fat mass, and cognitive development).

Results: We included 79 observational studies (N = 371,046). 'Low' to 'very low' certainty evidence revealed that compared with low levels of PA, high levels of PA before and during pregnancy were associated with a 13-25% reduction in the odds of having a preterm delivery (before pregnancy: odds ratio (OR): 0.87, 95% confidence interval (CI): 0.79 to 0.97; I 2 = 0%; during pregnancy: OR 0.75, 95% CI: 0.68 to 0.82; I 2 = 84%). High levels of PA during pregnancy were also associated with reduced odds of having a cesarean section (OR: 0.73, 95% CI: 0.62 to 0.87; I 2 = 89%). Other outcomes were not associated with PA. To achieve at least a 10% reduction in the odds of preterm birth, pregnant women need to accumulate at least 216 MET mins/week of leisure time physical activity.

Conclusions: Observational evidence suggests that higher physical activity levels before and during pregnancy may be associated with improved birth outcomes.