Relationship between ABO blood groups and gestational hypertensive disorders A protocol for systematic review and meta-analysis

Background: The distribution of ABO blood group is related to the incidence of various diseases. Gestational hypertensive disorders (GHD) is one of the most important risk factors during pregnancy, which has certain heredity. It is reported that ABO blood type is associated with the risk of GHD. However, the results are still controversial. In this study, we conducted a systematic review and meta-analysis to clarify the relationship between ABO blood group and GHD. Methods: All eligible studies come from Embase, Cochrane Library, Pubmed, Chinese databases SinoMed, Chinese National Knowledge Infrastructure, Chinese Scientific Journals Database, and Wanfang Data. The retrieval time is from the establishment of the database to March 2021. The language will be limited to Chinese and English. The 2 reviewers will be responsible for the selection of the study, the extraction of data, and the evaluation of the quality of the research. Pooled odds ratios (ORs) with 95% confidence intervals (CIs) were used to assess the corresponding associations. Sensitivity analysis, publication bias assessment, and heterogeneity test were performed using STATA 16.0. Results: The results of this meta-analysis will be published in peer-reviewed journals. Conclusion: This study will provide evidence to support the relationship between ABO blood group and the risk of GHD. Ethics and dissemination: The private information from individuals will not be published. This systematic review also will not impair endangering participants' rights. Ethical approval is not required. The results may be published in a peer-reviewed journal or disseminated in relevant conferences. OSF Registration number: DOI 10.17605/OSF.IO/3X9YZ.