Comparison of factors associated with postpartum depression from two cohorts of nurses: the Korea Nurses’ Health Study and the Nurses’ Health Study 3

Objectives This study aimed to identify whether differences exist in postpartum depression (PPD) in US and Korean nurses and its related factors. Identifying occupational and personal factors that underlie potential differences will be helpful for women’s occupational health. Methods Baseline and postpartum survey data from employed nurses in the Korea Nurses’ Health Study and Nurses’ Health Study 3 (1244 Korean; 2742 US nurses) were analysed. Postpartum data collection was done via online survey. PPD was analysed based on cultural validation from prior studies using the Edinburgh Postnatal Depression Scale (cut-off of 10 for Korea and 13 for USA); depressive symptoms prior to pregnancy and childbirth, general characteristics and sleep satisfaction were also measured. Descriptive statistics, χ2 tests and t-tests and multivariate ordinal logistic regression analysis were performed. Results 45.9% of Korean participants had clinical symptoms of PPD (≥10), whereas US participants presented with 3.4% (≥13). Prior depressive symptoms were also higher in Korean participants (22.5%) compared with their US counterparts (4.5%). Prior depressive symptoms and poor sleep satisfaction were significant risk factors of PPD in both cohort groups, and vaginal birth was an additional influencing factor in Korean participants. Conclusions Differences in PPD rates and related factors suggest the role of stress, cultural variation and differing work systems. Nurses and other women shift-workers noted to have depressive symptoms before and during pregnancy and exhibit PPD symptoms should especially be followed closely and offered supportive mental health services that include greater flexibility in returning to work.