Selection criteria
To be eligible, studies had to meet the following criteria: (1) postpartum women aged over 18 years with singleton live birth; (2) postpartum women experienced birth trauma (including physical birth trauma and/or psychological birth trauma); (3) postpartum women presented the three types of symptoms of PTSD (re-experiences, avoidance reminders, and hyperarousal) together for at least one month; (4) be published in English or Chinese; and (5) cohort study and cross-sectional study.
Studies were excluded for the following reasons: (1) participants with a history of PTSD or a PTSD prior to childbirth; (2) trauma events other than birth related, mental illness or psychological disease, personality disorder, intellectual disability, and cognitive impairment or brain diseases; (3) participants with severe pregnancy complications such as pregnancy with heart disease, hypertensive disorder complicating pregnancy, and gestational diabetic mellitus; and (4) unable to obtain relevant data (e.g. the number of trauma birth/ PTSD).