Abstract
Background: Depression and post-traumatic stress disorder (PTSD) are prevalent in pregnancy, especially among military members. These conditions can lead to adverse birth outcomes, yet, there's a paucity of evidence for prevention strategies. Optimizing physical fitness is one understudied potential intervention. We explored associations between prepregnancy physical fitness and antenatal depression and PTSD in soldiers. Materials and Methods: This was a retrospective cohort study of active-duty U.S. Army soldiers with live births between 2011 and 2014, identified with diagnosis codes from inpatient and outpatient care. The exposure was each individual's mean Army physical fitness score from 10 to 24 months before childbirth. The primary outcome was a composite of active depression or PTSD during pregnancy, defined using the presence of a code within 10 months before childbirth. Demographic variables were compared across four quartiles of fitness scores. Multivariable logistic regression models were conducted adjusting for potential confounders selected a priori. A stratified analysis was conducted for depression and PTSD separately. Results: Among 4,583 eligible live births, 352 (7.7%) had active depression or PTSD during pregnancy. Soldiers with the highest fitness scores (Quartile 4) were less likely to have active depression or PTSD in pregnancy (Quartile 4 vs. Quartile 1 adjusted odds ratio 0.55, 95% confidence interval 0.39-0.79). Findings were similar in stratified analyses. Conclusion: In this cohort, the odds of active depression or PTSD during pregnancy were significantly reduced among soldiers with higher prepregnancy fitness scores. Optimizing physical fitness may be a useful tool to reduce mental health burden on pregnancy.