Interpretation
In order to better understand PPD and to develop targeted prevention practices, several studies have attempted to define subtypes of PPD according to the time of onset, severity or predominant symptoms (5–8). In this study, we chose to distinguish PPD according to the onset of symptoms. Early and late PPD share some common pre-disposing factors: namely a personal history of depressive disorder and stressful life events during pregnancy. However, the two trajectories can also be distinguished: by socio-economic correlates, life events, and associated psychiatric disorders.