ObjectiveTo investigate risk factors for childbirth-related post-traumatic stress disorder (CR-PTSD) measured 1-month after first childbirth, and the association between CR-PTSD and maternal-infant bonding. MethodsIn this prospective cohort study 3006 nulliparous women living in Pennsylvania, USA, were asked about CR-PTSD at 1-month postpartum, and maternal-infant bonding at 1, 6 and 12-months postpartum. Multivariable logistic regression models identified risk factors for CR-PTSD and associations between CR-PTSD and maternal-infant bonding at 1, 6 and 12-months postpartum, controlling for confounding variables - including postpartum depression, stress and social support. ResultsNearly half (47.5%) of the women reported that during labor and delivery they were afraid that they or their baby might be hurt or die, and 225 women (7.5%) reported experiencing one or more CR-PTSD symptoms at 1-month postpartum. Depression, stress and low social support during pregnancy were associated with CR-PTSD, as well as labor induction, delivery complications, poor pain control, and unplanned cesarean delivery. Women with CR-PTSD reported a less positive childbirth experience, less shared decision-making, and were more likely to score in the bottom third on maternal-infant bonding at 1-month postpartum (adjusted odds ratio [aOR] 2.5, 95% CI 1.8–3.3, p < 0.001); at 6-months postpartum (aOR 2.1, 95% CI 1.5–2.8, p < 0.001); and at 12-months postpartum (aOR 2.2, 95% CI 1.6–3.0, p < 0.001). ConclusionIn this large-scale prospective cohort study we found that CR-PTSD was consistently associated with lower levels of maternal-infant bonding over the course of the first year after first childbirth.