Exercise frequency and maternal mental health: Parallel process modelling across the perinatal period in an Australian pregnancy cohort

Objective: Since the potential mental health benefits of exercise during pregnancy remain unclear, this study examined longitudinally the bidirectional relationship between exercise and maternal mental health symptoms during the perinatal period, and included adjustment for both depression and antidepressant treatment. Methods: Data were collected across pregnancy (first and third trimesters) and the postpartum (six and 12 months) for 258 women drawn from an Australian pregnancy cohort, the Mercy Pregnancy and Emotional Wellbeing Study (MPEWS). The women were assessed for depression using the EPDS, anxiety using the STAI and a clinical diagnostic interview (SCID-IV), and self-reported use of antidepressants. Exercise was measured using self-reported weekly frequency of 30-min bouts of moderate to vigorous exercise, and data were analyzed using parallel process growth curve modelling. Results: On average, women's weekly exercise frequency declined during pregnancy, returning to first trimester levels by 12 months postpartum. Women with depression and taking antidepressants reported lower first trimester exercise compared to control women. However, where non-medicated depressed women remained lower and continued to decline to 12 months, women taking antidepressants reported increasing levels of exercise during the perinatal period. Notably, a steeper decline in exercise frequency during the perinatal period was associated with a faster rate of increase in depressive and anxiety symptoms. Conclusions: This study is the first to examine the longitudinal interaction between exercise and mental health symptoms across the perinatal period. These preliminary findings demonstrate potential benefits for depressive and anxious symptoms when maintaining levels of early-pregnancy exercise throughout pregnancy and the postpartum.