From the third month of pregnancy to 1 year postpartum. Prevalence, incidence, recurrence, and new onset of depression. Results from the perinatal depression-research & screening unit study.

Objective: Perinatal depression is a particular challenge to clinicians, and its prevalence estimates are difficult to compare across studies. Furthermore, to our knowledge, there are no studies that systematically assessed the incidence of perinatal depression. The aim of this study is to estimate the prevalence, incidence, recurrence, and new onset of Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, minor and major depression (mMD) in an unselected population of women recruited at the third month of pregnancy and followed up until the 12th month postpartum.

Method: One thousand sixty-six pregnant women were recruited. Minor and major depression was assessed in a naturalistic, longitudinal study. The Edinburgh Postnatal Depression Scale and the Structured Clinical Interview for Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Disorders were administered at different time points during pregnancy and in the postpartum period.

Results: The period prevalence of mMD was 12.4% in pregnancy and 9.6% in the postpartum period. The cumulative incidence of mMD in pregnancy and in the postpartum period was 2.2% and 6.8%, respectively. Thirty-two (7.3%) women had their first episode in the perinatal period: 1.6% had a new onset of depression during pregnancy, 5.7% in the postpartum period.

Conclusions: Our postpartum prevalence figures, which are lower than those reported in the literature, may reflect treatment during the study, suggesting that casting a multiprofessional network around women in need of support may be potentially useful for reducing the effects of this disorder on the mother and the newborn child. Furthermore, our results indicate that women with a history of depression have a 2-fold risk of developing mMD in the perinatal period.