Expressive writing (EW) is a common psychological intervention that aims to improve the mental health of traumatized individuals. Pregnancy is considered an anxious or traumatic experience for some women, and any crisis in relation to pregnancy is closely associated with their psychological well-being. Post-traumatic stress disorder (PTSD), depression, anxiety and stress are the most prominent emotional and psychological responses that may occur during the process. However, the effects of EW in mediating women’s PTSD, depression, anxiety and stress related to pregnancy remain uncertain, and no qualified meta-analysis has assessed such effects. The aim of this study was to assess the effectiveness of EW as a psychological intervention for women. Five databases, including PubMed, EMBASE, Cochrane, Web of Science and PsycINFO, were searched from inception to September 2019 for eligible studies. Finally, a total of 929 participants from 8 randomized controlled trial (RCT) studies were included. A pooled analysis demonstrated that EW was an efficient therapy for decreasing PTSD. However, the results showed that the EW intervention was not associated with the expected effects on anxiety and stress symptoms. The efficacy of EW for depression was inconclusive. More RCTs are necessary to verify the effectiveness of EW for depression. Studies concentrating on EW’s effects on physical symptoms are necessary, and researchers should create an EW intervention group, neutral writing group and no writing group to examine the true effects of EW. Future research should examine whether longer, more frequent, and more targeted writing interventions would result in different conclusions.Copyright © 2020 Elsevier B.V. All rights reserved.