Incidence of maternal venous thromboembolism in China: A systematic review and meta-analysis

Background: Venous thromboembolism (VTE) is one of the primary causes of maternal death. Although many studies have reported maternal VTE, no study has estimated the incidence of it in China.Objectives: The aim of this work was to estimate the incidence of maternal VTE in China and to compare the risk factors for it.Search strategy: The authors searched eight platforms and databases including PubMed, Embase, and Cochrane Library from inception to April 2022, with the search terms "venous thromboembolism" AND "puerperium (pregnancy)" AND "incidence" AND "China."Selection criteria: Studies provide data to calculate the incidence of maternal VTE among Chinese patients.Data collection and analysis: The authors made a standardized table to collect data and calculated the incidence and 95% confidence intervals (CIs), founding source of heterogeneity by subgroup analysis and meta-regression and judging publication bias by funnel plot and Egger test.Main results: The included 53 papers with a total sample size of 3 813 871 patients had 2539 cases of VTE, and the incidence of maternal VTE in China was 0.13% (95% CI, 0.11-0.16; P < 0.001).Conclusions: The trend in the incidence of maternal VTE in China is stable. Cesarean section and advanced age are associated with a higher incidence of VTE.