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Meta-Analysis
. 2021 Aug;47(8):2565-2576.
doi: 10.1111/jog.14834. Epub 2021 May 17.

Prenatal anemia and postpartum hemorrhage risk: A systematic review and meta-analysis

Moshood O Omotayo  1   2 , Ajibola I Abioye  3   4 , Moshood Kuyebi  5 , Ahizechukwu C Eke  6
Affiliations
Meta-Analysis

Prenatal anemia and postpartum hemorrhage risk: A systematic review and meta-analysis

Moshood O Omotayo et al. J Obstet Gynaecol Res. 2021 Aug.

Abstract

Introduction: Postpartum hemorrhage (PPH) has remained the leading cause of maternal mortality. While anemia is a leading contributor to maternal morbidity, molecular, cellular and anemia-induced hypoxia, clinical studies of the relationship between prenatal-anemia and PPH have reported conflicting results. Therefore, our objective was to investigate the outcomes of studies on the relationships between prenatal anemia and PPH-related mortality.

Materials and methods: Electronic databases (MEDLINE, Scopus, ClinicalTrials.gov, PROSPERO, EMBASE, and the Cochrane Central Register of Controlled Trials) were searched for studies published before August 2019. Keywords included "anemia," "hemoglobin," "postpartum hemorrhage," and "postpartum bleeding." Only studies involving the association between anemia and PPH were included in the meta-analysis. Our primary analysis used random effects models to synthesize odds-ratios (ORs) extracted from the studies. Heterogeneity was formally assessed with the Higgins' I2 statistics, and explored using meta-regression and subgroup analysis.

Results: We found 13 eligible studies investigating the relationship between prenatal anemia and PPH. Our findings suggest that severe prenatal anemia increases PPH risk (OR = 3.54; 95% CI: 1.20, 10.4, p-value = 0.020). There was no statistical association with mild (OR = 0.60; 95% CI: 0.31, 1.17, p-value = 0.130), or moderate anemia (OR = 2.09; 95% CI: 0.40, 11.1, p-value = 0.390) and the risk of PPH.

Conclusion: Severe prenatal anemia is an important predictive factor of adverse outcomes, warranting intensive management during pregnancy. PROSPERO Registration Number: CRD42020149184; https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=149184.

Keywords: maternal mortality; meta-analysis; obstetric emergency; postpartum hemorrhage risk factors; postpartum hemorrhage-related mortality; prenatal anemia; systematic review.

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Conflict of interest statement

Conflict of interest

The authors have nothing to disclose.

Figures

Figure 1
Figure 1
Forest plot of the association between anemia and postpartum hemorrhage
Figure 2
Figure 2
Scatterplot of the association between categories of anemia severity and PPH
Figure 3
Figure 3
Forest plot of the association between severe anemia and PPH
See this image and copyright information in PMC

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