Background: Identifying factors that are predictive for postpartum posttraumatic stress disorder (PTSD) is important to inform clinical and research practice. Yet prospective longitudinal studies investigating symptoms of postpartum PTSD and their prevalence, evolution, comorbidities, and predictors remain limited. The aim of this study was to estimate the prevalence of women's symptoms of PTSD at different times in the postpartum period and to identify comorbidities and predictive factors in a French-speaking sample.Methods: A total of 168 women participated in this longitudinal study, which included 3 assessment points: immediate postpartum, 2 months postpartum, and 6 months postpartum. Participants filled out questionnaires regarding sociodemographic characteristics, pregnancy, and birth outcomes; subjective perceptions of birth; and symptoms of depression, anxiety, and PTSD.Results: Among the participants, 11.7% reported having symptoms of PTSD 2 months after birth and 10.5% reported having symptoms 6 months after birth. Regarding comorbidities and associated factors, depressive symptoms, poor marital adjustment, and impaired maternal-infant bonding were significantly and positively correlated with symptoms of PTSD. Peritraumatic distress, negative perceived childbirth experience, and complications and perceived difficulties during birth were predictive factors for postpartum PTSD.Discussion: More than 1 in 10 women experienced symptoms of postpartum PTSD. Health care professionals need to be aware of symptoms of postpartum PTSD, predictive factors, and comorbidities to be able to better identify women presenting those symptoms and refer them for appropriate psychological support.