(166) Associations between physical fitness, depression, and PTSD during pregnancy among U.S. Army soldiers

Objective: Depression and post-traumatic stress disorder (PTSD) are prevalent in pregnancy, especially among military members. Strong data suggests these conditions lead to adverse birth outcomes, yet there’s a paucity of evidence for effective preventive interventions. Optimizing physical fitness is one potentially promising intervention that has been understudied. We explored baseline associations between pre-pregnancy physical fitness and perinatal mental health conditions in soldiers.

Study Design: This was a retrospective cohort study of active-duty U.S. Army soldiers with livebirths between 2011 and 2014. Outcomes were ascertained using diagnosis codes from in- and outpatient care. The exposure was each individual’s army physical fitness score from 10-24 months prior to delivery, averaged if there were multiple. The primary outcome was a composite of active depression or PTSD during pregnancy, defined using the presence of a code for either diagnosis within 10 months prior to delivery. Demographic variables were compared between people with higher (>50th percentile) versus lower ( < 50th percentile) fitness scores. Multivariable logistic regression models were conducted adjusting for potential confounders, modeling per 10-unit fitness score increments.

Results: Among 52,055 female active-duty soldiers, 11,986 had eligible livebirths and 4,675 additionally had fitness scores available 10-24 months prior. 361 (7.7%) had depression or PTSD during pregnancy. Demographics varied by fitness scores (Table 1). People with higher fitness scores were less likely to have active depression or PTSD during pregnancy (aOR 0.96, 95% CI 0.93-0.99, Table 2). Findings were similar when examining fitness scores and active depression only (aOR 0.96, 95% CI 0.93-0.99), as well as active PTSD only (aOR 0.97 (0.93-1.00).

Conclusion: In this cohort of soldiers, for every 10 point increase in pre-pregnancy physical fitness score, the odds of active depression or PTSD during pregnancy decreased by 4%. Physical fitness may be a useful tool to reduce mental health burden in pregnancy.