Abstract Background Symptoms of both depression and Post-Traumatic Stress Disorder (PTSD) are prevalent among first-time mothers following birth. However, the direction of the association between the two types of symptoms is unclear. Methods Ninety six first-time mothers giving birth via vaginal delivery (N=38), emergency C-Section (N=27) and planned C-Section (N=21) were assessed for depression and PTSD twice: Six weeks post-partum and six-weeks later. Results Cross-lagged Structural Equation Modeling (SEM) analyses revealed a prospective effect of depressive symptoms on PTSD symptoms. No moderating factors were identified. Limitations A relatively modest sample size and only two assessment waves. Conclusions An early detection and intervention with symptoms of post-partum depression might also prevent the development of PTSD symptoms.