BACKGROUND: Globally the preterm birth rate for 184 countries in 2010 was 11.1%. Preterm births can be a traumatic experience for mothers. OBJECTIVE: This article provides a mixed research synthesis of the quantitative and qualitative studies on posttraumatic stress in mothers who have given birth prematurely. DESIGN: Narrative synthesis was the mixed research synthesis approach used. RESULTS: Included in this narrative synthesis were quantitative prevalence studies (n = 19), quantitative intervention studies (n = 6), and qualitative studies (n = 5). Prevalence rates ranged from 14% to 79%. Four of the intervention studies had significant results and two did not. Qualitative data synthesis revealed five themes: (a) shocked and horrified, (b) consuming guilt, (c) pervasive anxiety and hypervigilance, (d) intrusive thoughts, and (e) numbing and avoiding reminders. CONCLUSIONS: Women’s traumatic experiences of preterm birth are clearly important issues for psychiatric nurses to address.