Search strategy
Four English databases (CINAHL, PsycINFO, Embase and PubMed) and two Chinese databases (China National Knowledge Infrastructure [CNKI] and Wanfang) were searched from inception to 28 February 2022. Advanced searches were performed using a combination of two groups of terms according to the syntax rules of each database: (1) birth trauma-related terms including birth trauma, traumatic delivery, perceived birth trauma, physical birth trauma, and psychological birth trauma, and (2) PTSD-related terms including stress disorders, post-traumatic, post-traumatic stress disorder, PTSD, delayed onset post-traumatic stress disorder, chronic post-traumatic stress disorder, and acute post-traumatic stress disorder. The reference lists of all the related reviews and guidelines as well as electronically retrieved articles selected for inclusion in the present review were hand-searched to ensure comprehensive coverage of all relevant literature. Prior to the final analyses, the search was repeated to allow the inclusion of any newly published studies. As an example, the search strategy used with PubMed is presented (see Appendix S1).