Physical Activity and Risk of Preterm Birth in a Cohort of African American Women.

Abstract

Few studies have identified modifiable risk factors that are associated with the prevention of preterm delivery (PTD). This study examined the relationship between PTD and physical activity during pregnancy. Data were obtained by medical record review and postpartum questionnaires from a cohort of African American women (N=1,410) delivering singleton infants. Physical activity was self-reported and analyses compared any and none. Additional analyses classified leisure time physical activity (LTPA) and walking for a purpose as 0, 1 to 19, 20 to 39, and 40minutes per day or more and stair climbing as 0, 1 to 5, 6 to 9, and 10 or more times per day. Log-Poisson models adjusted for previous PTD, pregnancy complications, and income were used to examine the association between PTD and physical activity during pregnancy across body mass index categories. Overall, 16.4% of deliveries were preterm. LTPA was associated with a decreased prevalence of PTD (prevalence ratio [PR], 0.73; 95% confidence interval [CI], 0.55-0.96), but stratification by maternal prepregnancy body mass index suggested that LTPA was only protective against PTD among women with normal weight (PR, 0.43; 95% CI, 0.23-0.79). Stair climbing 10 or more times per day was associated with a decreased prevalence of PTD among women with normal weight (PR, 0.32; 95% CI, 0.11-0.94) and women with overweight (PR, 0.24; 95% CI, 0.07-0.80) only. Walking for a purpose (e.g., to the store, the bus stop, or to work) was not associated with PTD. African American women who participate in either LTPA or stair climbing during pregnancy have a decreased prevalence of PTD, but the protective effect varied by maternal body mass index.