The Global Prevalence of Thrombocytopenia among Pregnant Women: A Systematic Review and Meta‑Analysis

Background: Thrombocytopenia (TCP) is a common disorder during pregnancy. Its prevalence among pregnant women is four times greater than nonpregnant women. Objectives: This study aimed at determining the global prevalence of TCP among pregnant women. Methods: This systematic review and meta‑analysis was conducted in 2018. The PubMed, Scopus, Google Scholar, Magiran, and IranMedex databases were searched using the following key words: “TCP,” “pregnancy,” “pregnant,” “pregnant women,” “gestational,” and “platelets.” The titles and the abstracts of the retrieved studies were screened to identify potentially relevant studies. Articles were included if they were the reports of original researches, included data on the prevalence of TCP among pregnant women, were in English or Persian, and had been published from January 1, 2000 to September 1, 2018. Eligible studies were appraised using the Strengthening the Reporting of Observational Studies in Epidemiology checklist. Finally, a data collection form was used to extract data. The overall prevalence of TCP among pregnant women was estimated using meta‑analysis and the Comprehensive Meta‑Analysis Software. Heterogeneity was evaluated through the Chi‑square test and the I2 statistic, and funnel plot was used to evaluate the possibility of publication bias. Results: Among 1592 studies retrieved during literature search, sixteen were included in meta‑analysis. The overall prevalence of TCP among pregnant women based on the random effects model was 8.4% (95% confidence interval: 6.9%–10.1%). The lowest TCP prevalence was 4.3% in Taiwan, while the highest prevalence was 15.3% in Ghana. Gestational TCP was the most common cause of TCP among pregnant women. Conclusion: With a global prevalence of 8.4%, TCP in pregnancy affects around one‑tenth of pregnant women in the world. Thus, timely diagnostic, preventive, and therapeutic measures are needed to effectively manage TCP in pregnancy.