Physical Activity, Chronic Stress, and Inflammation in Mothers during the First Postpartum Year
Chronic stress predicts a number of adverse health outcomes, including depression, cardiovascular disease, and all-cause mortality. In the context of women's reproductive health, chronic stress exposure has been associated with increased risk of adverse birth outcomes and postpartum depression. Systemic inflammation resulting from immune system dysregulation is one of the pathways through which chronic stress is thought to influence physical health outcomes. Increasingly strong evidence suggests that engaging in regular physical activity protects individuals from the health-damaging effects of stress, possibly through alterations of biological stress responses. The present research pursued two main objectives using data from a prospective investigation conducted by academic researchers and community members at five collaborating sites across the U.S. These objectives were: 1) describing the levels and correlates of physical activity at six months postpartum in mothers of three ethnic/racial groups and different levels of SES including a large proportion who are poor and; 2) developing and testing multivariate models of the combined influence of chronic stress, physical activity, and other resilience resources on C-reactive protein (CRP), a marker of systemic inflammation that is associated with elevated risk of chronic disease.
Results indicated that African American race, Latina ethnicity, and living in a rural area were generally associated with lower levels of physical activity, whereas working outside the home was associated with high activity. In analyses predicting CRP, women with higher Financial Stress one month after the birth of child had higher CRP at both six months and one year postpartum. Notably, these subjective appraisals of Financial Stress were stronger predictors of inflammation than more objective resource indicators such as income and education. Additional analyses using structural equation modeling demonstrated that this relationship was mediated by adiposity. There was no evidence that behavioral or psychological resilience resources moderated the associations between chronic stressors and CRP. These findings advance existing knowledge by identifying correlates and predictors of important health outcomes during the first postpartum year.