Physical activity in pregnancy and adverse birth outcomes.

This study focused on the association between physical activity in the second trimester of pregnancy and adverse perinatal outcomes: low birth weight (LBW), preterm birth (PTB), and intrauterine growth restriction (IUGR). The study used a sample from the BRISA cohort, São Luís, Maranhão State, Brazil, which included women with singleton pregnancy, gestational age from 22 to 25 weeks confirmed by obstetric ultrasound performed at < 20 weeks, and re-interviewed in the first 24 hours postpartum (n = 1,380). Level of physical activity was measured by the International Physical Activity Questionnaire (IPAQ), short version, categorized as high, moderate, and low. A directed acyclic graph (DAG) was used to identify minimum adjustment to control confounding. High physical activity was not associated with LBW (RR = 0.94; 95%CI: 0.54-1.63), PTB (RR = 0.86; 95%CI: 0.48-1.54), or IUGR (RR = 0.80; 95%CI: 0.55-1.15). The results support the hypothesis that physical activity during pregnancy does not result in adverse perinatal outcomes.