The synergistic effect of breastfeeding discontinuation and cesarean section delivery on postpartum depression: A nationwide population-based cohort study in Korea.

Background: The relationships between breastfeeding discontinuation and cesarean section delivery, and the occurrence of postpartum depression (PPD) remain unclear. Therefore, we aimed to investigate the association of breastfeeding discontinuation and cesarean section delivery with PPD during the first 6 months after delivery.

Methods: Data were extracted from the Korean National Health Insurance Service-National Sample Cohort for 81,447 women who delivered during 2004-2013. PPD status was determined using the diagnosis code at outpatient or inpatient visit during the 6-month postpartum period. Breastfeeding discontinuation and cesarean section delivery were identified from prescription of lactation suppression drugs and diagnosis, respectively. Cox proportional hazards models were used to calculate adjusted hazard ratios.

Results: Of the 81,447 women, 666 (0.82%) had PPD. PPD risk was higher in women who discontinued breastfeeding than in those who continued breastfeeding (hazard ratio=3.23, P<0.0001), in women with cesarean section delivery than in those with vaginal delivery (hazard ratio=1.26, P=0.0040), and in women with cesarean section delivery who discontinued breastfeeding than in those with vaginal delivery who continued breastfeeding (hazard ratio=4.92, P<0.0001).

Limitations: Study limitations include low PPD incidence; use of indirect indicators for PPD, breastfeeding discontinuation, and working status, which could introduce selection bias and errors due to miscoding; and potential lack of adjustment for important confounders.

Conclusions: Breastfeeding discontinuation and cesarean section delivery were associated with PPD during the 6-month postpartum period. Our results support the implementation of breastfeeding promoting policies, and PPD screening and treatment programs during the early postpartum period.