Background: Anemia is one of the most critical health conditions affecting people worldwide. The disease is silent, with a slow progression and a few physical symptoms. Anemia during pregnancy carries the risk of premature birth, low birth weight, and fetus malformations and can impose additional costs on society and families. Therefore, the aim of this study is to conduct a systematic review and meta-analysis on the prevalence of anemia in pregnant women worldwide.

Methods: In this work, we have conducted a systematic review and meta-analysis of the studies that have examined the prevalence of anemia in pregnant women globally. The Google Scholar, Cochrane, ScienceDirect, Medline (PubMed), and Web of Science (WoS) databases were searched for articles published between 1991 and 2021. The search keywords were anemia, pregnancy, prevalence, and meta-analysis. In order to analyze the eligible studies, the stochastic effects model was used, and the heterogeneity of the studies was examined using the I² index. Data analysis was performed within the Comprehensive Meta-Analysis software (Version 2).

Results: The search resulted in 338 deduplicated studies, of which 52 studies with a total sample size of 1,244,747 people were included in this review. According to the results of the meta-analysis, the overall prevalence of anemia in pregnant women is 36.8% (95% confidence interval: 31.5-42.4%). The highest prevalence of anemia is mild at 70.8 (95% CI 58.1-81) and highest in the third trimester of pregnancy with the prevalence of 48.8 (95% CI 38.7-58.9), while the highest prevalence of anemia in pregnant women was in Africa with the prevalence of 41.7 (95% CI 32.3-49.4).

Conclusion: The results of this study show a high prevalence of anemia among pregnant women worldwide, and the highest of this prevalence is mild anemia. The prevalence of anemia in the third trimester was higher than in the first and second trimesters. Anemia in pregnant women in developing countries is significantly higher than in developed countries due to pregnancy's economic, sociological, and health factors.