Maternity blues as predictor of postpartum depression: a prospective cohort study among Japanese women.

Background. Maternity blues and postpartum depression are common complications of childbearing. However, few studies have shown the relationship between the severity of maternity blues and the risk of postnatal depression. We carried out a longitudinal study among Japanese women to show that maternity blues is a useful factor for predicting postpartum depression.Methods. Two hundred and thirty-five women completed questionnaires before delivery, and five days, one month, and three months after delivery. They were required to answer the Stein's Blues Scale and Edinburgh Postnatal Depression Scale and other variables. A sequential logistic regression analysis was performed to estimate the association of maternity blues with postpartum depression. The stratum-specific likelihood ratio was then calculated.Results. The prevalence of postpartum depression was 12.8%. A Stein's Blues Scale of eight or above was significantly associated with postnatal depression. Likelihood ratios (95% CI ) for the Stein's Blues S...