Physical Activity and Its Relationship with Preterm Birth in the Presence of Depressive Symptomology.

OBJECTIVE To examine the relationship between physical activity (PA) and preterm birth (PTB) within the context of depressive symptoms (DS). METHODS Data are from the Life-course Influences of Fetal Environments (LIFE) Study, a cohort comprised of 1410 Black women, age 18-45 years who delivered a singleton in Metropolitan Detroit, MI. DS were measured with the Center for Epidemiologic Studies Depression Scale (CES-D); a score > 23 indicates severe DS. Traditional leisure time PA (LTPA) and non-LTPA during pregnancy (walking for a purpose, climbing stairs) were both measured. Modified Poisson regression models were used to estimate the association between PTB and PA. Effect modification by severe DS was assessed via stratification. RESULTS Approximately 16% of women had a PTB; 20% had CES-D scores > 23. Walking for a purpose was the most frequently reported type of PA (79%), followed by any LTPA (37.7%) and climbing stairs (13.5%). Compared with women who reported no PA, women who reported walking for a purpose (PR = 0.70, 95% CI 0.61, 1.10), partaking in LTPA (PR = 0.67, 95% CI 0.50, 0.90), or climbing stairs (PR = 0.61, 95% CI 0.45, 0.81) were less likely to have PTB. Results stratified by severe DS show the association between LTPA and PTB was more pronounced in women with severe DS, while the non-LTPA relationship with PTB was more heterogeneous. CONCLUSIONS Women who participated in traditional LTPA (any or walking only) and non-LTPA experienced improved birth outcomes. LTPA may buffer against PTB among pregnant Black women with severe DS as well as none or mild DS.