  Background: IGEDEPP (Interaction of Gene and Environment of Depression during
PostPartum) is a prospective multicenter cohort study of 3,310 Caucasian women
who gave birth between 2011 and 2016, with follow-up until one year postpartum.
The aim of the current study is to describe the cohort and estimate the
prevalence and cumulative incidence of early and late postpartum depression
(PPD). Methods: Socio-demographic data, personal and family psychiatric
history, as well as stressful life events during childhood and pregnancy were
evaluated at baseline. Early and late PPD were assessed at 8 weeks and 1 year
postpartum respectively, using DSM-5 criteria. Results: The prevalence of early
PPD was 8.3% (95%CI 7.3-9.3), and late PPD 12.9% (95%CI 11.5-14.2), resulting
in an 8-week cumulative incidence of 8.5% (95%CI 7.4-9.6) and a one-year
cumulative incidence of PPD of 18.1% (95%CI: 17.1-19.2). Nearly half of the
cohort (N=1571, 47.5%) had a history of at least one psychiatric or addictive
disorder, primarily depressive disorder (35%). Almost 300 women in the cohort
(9.0%) reported childhood trauma. During pregnancy, 47.7% women experienced a
stressful event, 30.2% in the first 8 weeks and 43.9% between 8 weeks and one
year postpartum. Nearly one in five women reported at least one stressful
postpartum event at 8 weeks. Conclusion: Incident depressive episodes affected
nearly one in five women during the first year postpartum. Most women had
stressful perinatal events. Further IGEDEPP studies will aim to disentangle the
impact of childhood and pregnancy-related stressful events on postpartum mental
disorders.
