OBJECTIVE: We investigated whether physical activity is associated with psychobiological improvements in pregnant individuals with symptoms of depression.
METHODS: This secondary analysis used data from a prospective cohort in Singapore (2009-2010). We included pregnant participants at 26-28 weeks' gestation with depressive symptoms (Edinburgh Postnatal Depression Scale [EPDS] score ≥9). The primary outcome was maternal leukocyte telomere length (a marker of cumulative stress and biological aging), measured from buffy coat at 26-28 weeks using quantitative polymerase chain reaction and expressed as telomere/single gene (T/S) ratios. We examined 1) cross-sectional association of EPDS scores with telomere length, 2) moderation by physical activity, and 3) whether telomere length and physical activity level in pregnancy predicted postpartum EPDS scores. Self-reported physical activity was categorized into none, moderate, or high amounts of moderate to vigorous physical activity (estimated from time spent and metabolic equivalent tasks). We used linear regression models, adjusting for confounders.
RESULTS: Among 169 participants, 36 (21%) were inactive, 95 (56%) had moderate physical activity levels, and 28 (17%) had high physical activity levels. Higher EPDS scores were associated with shorter telomeres among inactive participants (T/S effect -.03, 95% confidence interval [CI] [-.05, -.00]), but not in those with moderate (p-interaction .01) or high activity (p-interaction .06). Longer telomeres and higher physical activity during pregnancy were related to greater within-person decreases in EPDS scores by 3 months postpartum (ß estimate -17.6, 95% CI [-32.6, -2.6], p-interaction .02 for high physical activity).
CONCLUSION: Physical activity during pregnancy may buffer against stress-related maternal leukocyte telomere shortening, and this biological buffering effect may support better mental health outcomes by 3 months postpartum.
