Prevalence of rhesus D-negative blood type and the challenges of rhesus D immunoprophylaxis among obstetric population in Ethiopia: a systematic review and meta-analysis
Authors: Ayenew Asteray Assmie 
Published: February 2021

Abstract
Background
Transplacental or fetomaternal hemorrhage (FMH) may occur during pregnancy or at delivery and lead to immunization to the D antigen if the mother is Rh-negative and the baby is Rh-positive. This can result in hemolytic disease of the fetus and newborn (HDFN) in subsequent D-positive pregnancies. Therefore, the aim of this systematic review and meta-analysis was to estimate distribution of ABO and Rh (D) blood groups among pregnant women in Ethiopia.

Method
We searched PubMed, Google Scholar, EMBASE, Cochrane Library, HINARI, AFRO Library Databases, and African Online Journal databases for all available studies using the following keywords: “High rhesus (Rh(D)) negative frequency”, “ABO blood group distribution”, “haemolytic disease of the newborn (HDN)”, “rh isoimmunization”, “anti-RhD immunoglobulin”, “D-negative pregnancies”, “Frequency”, “ABO and Rh blood group distribution”, “feto-maternal hemorrhage”, “rhesus D negative pregnant mothers”, “kleihauer-betke test (KBT)”, “Neonatal Hyperbilirubinemia”, “non-sensitized RhD-negative pregnant women”, “antenatal anti-D immunoglobulin prophylaxis”, “Hemolytic disease of the newborn (alloimmunization), Ethiopia. The search string was developed using “AND” and “OR” Boolean operators. All published and unpublished observational studies reporting the distribution of ABO and Rh (D) blood groups among pregnant women in Ethiopia were included. The study participants were all pregnant women in Ethiopia, and the main outcome measure of this systematic review and meta-analysis was Rhesus D-negative blood type and ABO blood group distribution among pregnant women in Ethiopia. The data was extracted by the author (AAA) by using a standardized JBI data extraction format. Microsoft Excel (2016), and Stata version 11.0 (Stata Corporation, College Station, Texas, USA) software were used for data entry and analysis, respectively. The random effect model was used for estimating the pooled effects, and the publication bias was assessed by visual inspection of the funnel plots and objectively by using the Egger’s test (i.e. p < 0.05).

Results
One hundred thirty-two articles were identified through electronic database searching. Of which, 34 were excluded due to duplication, 65 through review of titles and abstracts, and 22 full-text articles were excluded for not reporting the outcome variable and other reasons. Finally, 7 were included to estimate the distribution of ABO and Rh (D) blood groups among pregnant women in Ethiopia. The pooled distribution of Rh-negative blood group among pregnant women in Ethiopia was 10.8% (95%CI: 7.53–14.07, I2 = 85%, p < 0.001). In the ABO system, type O was the most prevalent 39.9% (37.51–42.38), followed by A (30.59% (26.00–35.18)), B (23.04% (20.03–26.05)), and AB the least (4.82%(3.17–6.47)), in the pattern O > A > B > AB.

Conclusion
The pooled distribution of Rh-negative blood group among pregnant women in Ethiopia was high. Rh alloimmunization remains a major factor responsible for perinatal morbidity in Ethiopia and may result in the compromise of the woman’s obstetric care due to the unaffordability of anti-D immunoglobulin. There is the urgent need for the implementation of universal access to anti-D immunoglobulin for the Rh-negative pregnant population in Ethiopia.