Associations of Antenatal Corticosteroids and Maternal Postpartum Mental Health-A Cohort Study

Antenatal corticosteroid treatment (ACS), administered intramuscularly to pregnant women, is recommended as standard care when birth before 34 weeks of gestational age is anticipated. ACS is widely recognized for its ability to reduce neonatal mortality and morbidity, but it may affect maternal mental health due to its neuropsychiatric side effects and its timing during a period of heightened psychological vulnerability. Despite this, the potential association between ACS and maternal postpartum psychiatric disorders remains understudied. This study aimed to examine the possible associations between ACS and maternal postpartum depression and other postpartum psychiatric disorders.

This register-based cohort study included 165,936 births by 130,235 unique women at seven Danish hospitals between 2003 and 2018. Data on ACS administration, pregnancies, births, postpartum psychiatric disorders, and potential confounders were retrieved from Danish registers. The women were followed 1 year after giving birth for incident psychiatric disorders, and associations with ACS were explored in Cox proportional hazards regression models. The models were clustered by maternal ID and adjusted for sociodemographic, obstetric, and psychiatric covariates to estimate hazard ratios (HRs) with corresponding 95% confidence intervals (CIs). An interaction between gestational age and ACS exposure was included in all models.

Women who had been exposed to ACS but gave birth at term or post-term had significantly higher hazards of postpartum depression, other postpartum psychiatric disorders, and the combined outcome compared with non-exposed women giving birth at similar gestational ages, with HRs: 1.66 (1.18-2.33), 1.50 (1.03-2.19), and 1.64 (1.24-2.18), respectively. In contrast, associations among women who gave birth preterm were not statistically significant.

ACS exposure was associated with increased risks of maternal postpartum psychiatric disorders among women who gave birth term or post-term, but not among those who gave birth preterm. The increased risks in the term/post-term group are likely attributable to unmeasured confounding. These findings provide reassurance that ACS is unlikely to substantially increase the risk of postpartum psychiatric disorders among women delivering preterm, but they also highlight the need for attentive follow-up of women with threatened preterm labor who ultimately give birth at term. Our results also call for improved registration of ACS administration to strengthen future surveillance and drug safety.