Objective: This study reports the allelic and phenotypic frequency distribution of the ABO and Rh blood groups in pregnant women who attended antenatal care (ANC) at Zewditu Memorial Hospital in Addis Ababa, Ethiopia, and the likelihood for the occurrence of erythroblastosis fetalis (E. fetalis).

Methods: A retrospective study was conducted on pregnant women who attended ANC from 2015 to 2019 and typed for ABO and Rh blood groups. The Hardy–Weinberg equilibrium was used to determine the allelic frequency of ABO and Rh blood types. The likelihood of the occurrence of E. fetalis was computed.

Results: Among the 2453 women who had been admitted to ANC, 2407 (98.1%) pregnant women who had been typed for the ABO and Rh blood groups were included in this retrospective study. We found that Type O blood was the most common one (38.9%), while Types A (31.3%), B (23.8%), and AB (6.0%) blood were scored with modest to lower proportions. Among blood group–typed women, 94.2% were Rh-positive. The allelic frequency of O was 0.62, whereas A (0.22) and B (0.16) had modest proportions. The allelic frequency of D was 0.76 and d was 0.24. The likelihood of the occurrence of E. fetalis was 5%. Our findings show that both the ABO (χ-squared = 6.1439, df = 3, p value = 0.1048) and the Rh (χ-squared = 0.000103, df = 1, p value = 0.9919) blood groups were segregated at the Hardy–Weinberg proportions. Studies need to investigate the evolutionary forces that have made the ABO and Rh blood types segregate at the Hardy–Weinberg proportion.

1. Introduction

Blood grouping sorts blood based on the antigenic properties of the red blood cells (RBCs) [1–5]. The ABO blood group consists of two antigens, A and B, on the surface of the RBCs and two reciprocal antibodies (anti-A and anti-B) in the blood plasma (serum). Phenotypically, individuals who are homozygous dominant (DD) or heterozygous (Dd) are rhesus (Rh)-positive, whereas those who are homozygous recessive (dd) are Rh-negative [6]. Blood group antigens play an important role in transfusion medicine, in genetic studies, and in screening for disease susceptibility [7–9]. An Austrian scientist named Karl Landsteiner was the first to discover the ABO blood group system [1, 2]. Nearly 700 antigens have been identified in erythrocytes. The antigens are categorized into 44 blood group systems by the International Society of Blood Transfusion [10]. Among the blood group systems, the ABO and Rh blood types are the most important due to their use in blood transfusion [11]. According to the presence of antigens and agglutination patterns, the ABO blood group is divided into four types: A, B, O [1, 2], and AB [3].

The second-most important blood group type is Rh, which was discovered in the 1940s by Karl Landsteiner and Alexander Weiner [12, 13]. In the Rh blood group system, the Rh antigen, named after the antigen first discovered in Rh monkeys, is found on the surface of the RBC. Individuals who have the RhD antigen are Rh-positive, whereas those who lack it are Rh-negative. The frequencies of ABO and Rh blood groups could vary among populations sharing the same geographic region [14, 15].

For proper management of blood banks and safe blood transfusions, knowledge of the frequency distribution of ABO and Rh blood groups is crucial [8]. Blood transfusion refers to the transfer of blood or blood products from a donor to the recipient [16]. O-negative blood types are safe for everyone. Consequently, individuals with an O-negative blood type are referred to as universal donors. The O-negative blood type is used in emergency cases when there is no time to test the recipient’s blood type. On the other side, Type AB blood is a universal blood plasma donor. O is recessive to both the A and B alleles. The AB blood type is codominant and a universal recipient. Individuals who have Rh-positive blood can receive either Rh-positive or Rh-negative blood, but those who are Rh-negative can only receive Rh-negative blood [16].

Identifying the ABO and Rh blood groups is important, especially in transfusion medicine and to treat erythroblastosis fetalis (E. fetalis). Moreover, testing for blood types is vital in the Global South, where blood group screening practices are less common. This study reports the frequency distribution of the ABO and Rh blood groups in pregnant women who attended antenatal care (ANC) at Zewditu Memorial Hospital in Addis Ababa, Ethiopia.

2. Materials and Methods

2.1. The Study Sites and Population

The study was conducted at Zewditu Memorial Hospital in Addis Ababa, Ethiopia. Among the 12 public-owned hospitals in Addis Ababa, Zewditu Memorial Hospital was selected because it is the closest hospital to Gandhi Memorial Hospital, which specializes in maternity care. As a result, Zewditu Memorial Hospital is an immediate outlet for pregnant women when there is a spillover at Gandhi Memorial Hospital. Pregnant women who visited Zewditu Memorial Hospital for ANC from September 2015 to June 2019 and were typed for the ABO and Rh blood groups were included in this retrospective study.

2.2. The Study Designs

The medical histories of 2453 pregnant women who visited Zewditu Memorial Hospital were considered in this study, and out of these, 2407 had been typed for ABO and Rh blood groups. The ABO and Rh blood data were collected from four ANC departments and 10 ANC registration books.

2.3. Data Analysis

Inferences were made using the chi-square test and Cramer’s V test. The data were analyzed using SPSS Version 22 [17] and R [18]. When the p value is less than or equal to 0.05, the analysis is deemed significant.

2.4. Allelic and Genotypic Frequency Analyses

For the Rh blood group, the allelic frequencies were calculated using Equations (1) and (2), and the genotypic frequencies were calculated using Equations (3)–(5).

The allelic frequency is calculated as follows:

(1)

(2)

The genotypic frequency is calculated as follows:

(3)

(4)

(5)

The phenotypic frequency for the biallelic Rh factor with a complete dominance expression pattern was computed as

(6)

(7)

The Hardy–Weinberg equilibrium for the Rh factor was analyzed using Equation (8).

(8)

For the multiallelic ABO blood group, the allelic frequencies were calculated using Equations (9)–(11), and the genotypic frequencies were calculated using Equations (12)–(17).

(9)

The frequency of the A allele was obtained using the quadratic equation (Equation (10)).

(10)

The frequency of the B allele was calculated using Equation (11).

(11)

The genotypic frequency of ABO blood groups was calculated using Equations (12)–(17).

(12)

(13)

(14)

(15)

(16)

(17)

The Hardy–Weinberg equilibrium for the ABO blood group was analyzed using Equation (18).

(18)

Phenotypic frequencies were calculated using Equations (19)–(22).

(19)

(20)

(21)

(22)

The occurrence of E. fetalis was computed using Equation (23).

(23)

where p is the probability, DD is the homozygote dominant genotype, Dd is the heterozygote, and dd is the homozygote recessive genotype.

3. Results

3.1. Demographic Characteristics of the Pregnant Women

The demographic structure of the pregnant women who visited Zewditu Memorial Hospital for ANC and who were typed for the ABO and Rh blood groups shows a significant difference in most of the recorded demographic characteristics (Table 1). Few women were below the age of 19.

Table 1. Demographic characteristics of the study population.

Variables	Frequency	Percent
Age groups		χ-squared = 1737.2, df = 5, p value < 2.2e − 16
<19	50	2.0
20–24	607	24.7
25–30	980	40.0
31–34	562	22.9
35–39	224	9.1
40–45	16	0.7
Not recorded	14	0.5
Marital status		χ-squared = 6009, df = 3, p value < 2.2e − 16
Single	26	1.1
Married	2052	83.7
Divorced	2	0.1
Widowed	2	0.1
Not recorded	371	15.1
Educational status		χ-squared = 35.103, df = 1, p value = 3.128e − 09
Illiterate	1	0.0
Literate	38	1.6
Not recorded	2412	98.3
Employment status		χ-squared = 0.67123, df = 1, p value = 0.4126
Employed	40	1.6
Unemployed	33	1.3
Not recorded	2378	97.0

3.2. ABO and Rh Blood Group Frequencies

Type O blood was the most frequent and accounted for 38.9%, followed by A (31.3%), B (23.8%), and AB (6.0%). Among the blood group–typed women, 94.2% were Rh-positive (Figure 1). A statistically significant difference was observed between the proportions of the ABO (χ-squared = 576.39, df = 3, p value < 2.2e − 16) and Rh (χ-squared = 1886.1, df = 1, p value < 2.2e − 16) blood types. Our analysis shows that the ABO blood group alleles were segregated at the Hardy–Weinberg equilibrium (χ-squared = 6.1439, df = 3, p value = 0.1048). Likewise, for the Rh-factor allelic frequency, the population was at the Hardy–Weinberg equilibrium (χ-squared = 0.000103, df = 1, p value = 0.9919).

Details are in the caption following the image — **Figure 1**
Open in figure viewer PowerPoint

ABO and Rh blood groups of pregnant women who visited Zewditu Memorial Hospital from September 2015 to June 2019.

The result of cross-tabulation for ABO and Rh blood types is presented in Table 2. Cramer’s V analysis shows that there is a significant association between ABO and Rh blood types (V = 0.564, p < 0.001).

Table 2. Cross-tabulation of frequency counts of ABO and Rh blood groups.

ABO–Rh blood group	Rh blood group		Total
ABO–Rh blood group	Rh ⁺	Rh ⁻	Total
ABO blood group
A	705	49	754
B	544	28	572
AB	133	11	144
O	886	51	937
Total	2268	139	2407

3.3. Allelic and Genotypic Frequencies of ABO and Rh Blood Groups

The allelic frequency of d was 0.24; thus, D was 0.76. The allelic frequency of the O blood type was 0.62, A was 0.22, and B was 0.16. The frequencies of the six genotypic classes of the ABO blood group and the Rh factor are presented in Table 3.

Table 3. Genotypic frequencies of ABO and Rh blood groups.

Blood group genotypes	Equation	Genotypic frequencies
ABO
AA	p²	0.0484
AO	2pr	0.2728
BB	q²	0.0256
BO	2qr	0.1984
AB	2pq	0.0704
OO	r²	0.3844
Rh factor
DD	p²	0.5776
Dd	2pq	0.3648
dd	q²	0.0576

3.4. The Combined Genotypic Frequencies of ABO and Rh Blood Groups

The combined genotypic frequencies of the ABO and Rh blood groups are presented in Table 4. The likelihood of E. fetalis in the studied population can be estimated using the sum rule of probability. Accordingly, mating between DD men and dd women, plus half of the mating between Dd men and dd women, would have the chance of creating Rh-positive pregnancies carried by Rh-negative women. According to this data and by assuming similar allelic frequencies in male and female sex groups, the likelihood of the occurrence of the hemolytic reproductive disorder in fetuses and neonates is about 5%.

Table 4. The combined genotypic frequencies of ABO and Rh blood groups.

ABO and Rh blood group types	Rh blood group types
ABO and Rh blood group types	Rh ⁺	Rh ⁻
ABO blood group types
AA	0.036784	0.011616
AO	0.207328	0.065472
BB	0.019456	0.006144
BO	0.150784	0.047616
AB	0.053504	0.016896
OO	0.292144	0.092256

4. Discussions

A small percentage of young women were phenotyped for the ABO–Rh blood group because early marriage is not common in metropolitan Addis Ababa. However, this abhorrent practice is widespread in rural Ethiopia [19]. The data also subtly demonstrates that having children is typically linked to marriage, demonstrating the conservative mindset of this ancient nation’s residents who firmly thought that having children should be linked to common-law marriage [20]. The study assessed the frequency distribution pattern of ABO and Rh blood groups of pregnant women in Addis Ababa. The retrospective data was generated from demographically heterogeneous study subjects, corroborating its representativeness. In this study, Type O blood was the most frequent, and Type AB blood was the least. The rarity of Type AB blood is not surprising because it is the product of the joint probabilities of the two minor alleles A and B of the ABO blood group. In line with this finding, several studies conducted on the ABO blood group show that the frequency of Type O blood is the highest [21–24]. However, Type B blood is the most frequent in some regions of India [25], and Type A blood is most frequent in Japan [26] and in some tribal communities of India [21]. Blood group frequency could vary among ethnic groups and even across religious sects [21] and can be varied following environmental gradients [27]. Consanguine marriage instigated by religious dogmas may alter the allelic frequency by introducing homogeneity, which could also hold for blood types.

The high frequency of the O allele is observed regardless of its recessive expression pattern. However, being expressed in a recessive manner does not necessarily reflect the characteristics of a rare allele. Because O may possess a selective advantage, it has a high historical allelic frequency. Undoubtedly, in most parts of the world and likely across the globe, Allele O represents the major allele, and the Sibling A and B alleles represent minor alleles. According to Ségurel et al. [28], our close phylogenetic relatives like chimpanzees, gorillas, orangutans, and gibbons possess a high proportion of Types A and B blood, questioning the ancestral nature of the O allele. However, we need to recall the recessive expression pattern of Allele O, which does not enable it to be expressed in the heterozygote state (AO and BO). On the other hand, by analogy, this tells us that A and B alleles might be ancestral. However, O, which originated from a point mutation bringing about a frameshift mutation [29], is segregating at a higher frequency. This might be attributed to its selective advantage, which partly derives from the production of both A and B antibodies in the blood plasma [30]. It was believed to be ancient human races like the Red Indians of South America, and Eskimos possess a high frequency of Type O blood [27]. Types A and B blood sometimes reshuffle their ranking order of frequency count [31] as O and A do. However, Type AB blood invariably remains the least observed phenotype [31]. Because Type AB blood lacks both Antibodies A and B in the blood plasma, it might have lost some comparative adaptive advantages.

The Rh-positive allele is invariably the most common across the world. Subsequently, the Rh-positive allele represents the major allele. For example, in line with this study, the Rh-positive blood type is the most common one among several communities [21–24]. Consequently, the frequency distribution of the Rh-negative blood type is low. Regardless of the low proportion of Rh-negative blood, it needs due attention to reduce its adverse impact on the reproductive health of fetuses and neonates. Rh-negative blood type is extremely rare in Asia [32]; however, it is relatively common among Caucasian populations [33]. The Rh-negative allele might have arisen later in evolutionary history as a recessive mutation, which is why its frequency is much lower than that of the putative ancestral allele, Rh-positive. Rh-negative blood might have lost its selective advantage, especially regarding reproductive fitness. However, Rh-negative individuals are thought to be resilient to infections [8]. Although the ABO and Rh blood groups are encoded by different genes that are located on different chromosomes, the two blood groups are functionally linked.

E. fetalis accounts for about 3% of infant deaths [34], which is comparable to the likelihood of the incidence of E. fetalis reported in our study for both fetuses and neonates (5%). As it was described in the methodology section (Equation (23)), when an Rh-negative mother is immunized by the Rh-positive RBCs of the fetus, or when this mother is transfused with Rh-positive blood, E. fetalis could occur [35, 36]. However, besides the placental barrier between maternal and fetal blood, the actively growing fetus may, in some instances, produce sufficient blood through the process of extramedullary erythropoiesis in the spleen and liver [36]. Moreover, the strength of the antibody produced by the mother, the gestational stage, and the ability of the fetus to replenish the destroyed RBCs and clear bilirubin determine the impact of E. fetalis [37]. Once the Rh-negative mother was immunized using Rh(D) immune globulin, maternal antibodies to Rh-positive cells were not produced in subsequent pregnancies, making the pregnancies safe [37]. Although rare, anti-Kell E. fetalis is identical to the health disorder that is caused by anti-Rh(D) [38, 39]; therefore, disentangling the two pathophysiologies is essential for the effective treatment of the hemolytic disease of the fetus and neonate.

The Hardy–Weinberg equilibrium analyses exhibit statistically inconsequential differences among observed and expected ABO blood groups (p value = 0.1048) and Rh factor (p value = 0.9919) allelic proportions. The Hardy–Weinberg proportions can be attained regardless of nonrandom mating [40] and inherently outbreeding practices in human races. The maintenance at the Hardy–Weinberg proportion encountered regardless of the ABO blood group involves a complex expression pattern involving both complete dominance and codominance expression patterns at a locus level, multiallelism, intricate gene flow, and genetic admixture among human races. However, humans rarely consider blood types while selecting mates; hence, blood group types are little impacted by anthropogenic effects. Moreover, long-term balanced selection could have maintained the alleles at the Hardy–Weinberg proportion. Besides, even these days, a few individuals, especially in the Global South, are aware of their blood types. Often, there is no sex bias in the allelic frequencies of ABO and Rh blood groups [24], which enables to maintain the Hardy–Weinberg equilibrium. Because humans are sexually reproducing organisms and their population size is sufficiently large, these attributes can also contribute to the maintenance of the Hardy–Weinberg proportion. Humans might have relatively experienced neutral selection [41], which could be why they possess various alleles that are segregating at the Hardy–Weinberg proportion.

5. Conclusion

The phenotypic frequency distribution of the ABO blood group according to decreasing order of frequency count was O, A, B, and AB. Rh-positive was the most frequent. Both ABO and Rh blood groups were segregated at the Hardy–Weinberg proportion. This is regardless of the practice of nonrandom mating and expansive gene flow in humans. The outcome of this study will contribute its part to the blood transfusion process and take corrective measures on the adverse impact of E. fetalis. The findings of this study need to be corroborated using a large dataset involving study subjects with various demographic structures. Along with blood group typing, future studies need to focus on unraveling the evolutionary history of ABO and Rh blood group alleles and mapping the drivers of ABO and Rh blood group allelic frequency variations.

Ethics Statement

The DGRC approved and cleared the research proposal (KMU/Biol/318/2019). Zewditu Memorial Hospital collected the data as routine antenatal care practice. The Addis Ababa City Public Health Research and Emergency Management Directorate, Zewditu Memorial Hospital, allowed us to use the secondary data for research purposes only.

Consent

Informed verbal consent was obtained by the hospital from all the blood group–tested pregnant women.

Disclosure

To ensure the confidentiality of the information, the data that reveals the identity of the women was not recorded.

Conflicts of Interest

The authors declare no conflicts of interest.

Author Contributions

All authors (M.W.T., D.J.B., and T.T.D.) significantly contributed to the conceptualization, drafting, and revising of the manuscript. In addition, M.W.T. collected the data, and T.T.D. analyzed and interpreted the result.

Funding

No specific fund was received to conduct this study.

Acknowledgments

Zewditu Memorial Hospital is highly acknowledged for sharing the data.

Open Research

Data Availability Statement

The data used in this study will be available from the corresponding author upon reasonable request.

References

1 Landsteiner K., Zur kenntnis der antifermativen, lytischen und agglutinierenden Wirkungen des Blusterums und der Lymphe, Zbl Bakt. (1900) 27, 357–366.
Google Scholar
2 Landsteiner K., Über Agglutinationserscheinungen normalen menschlichen Blutes, Klein Wschr. (1901) 14, 1132–1134.
Google Scholar
3 von Decastello A. and Sturli A., Ueber die Isoagglutinine im Serum gesunder und kranker Menschen, Munch med Wchnschr. (1902) 49, 1090–1095.
Google Scholar
4 Kabat E. A., Blood Group Substances; Their Chemistry and Immunochemistry, 1955, Academic Press, New York.
Google Scholar
5 Watkins W. M., Biochemistry and genetics of the ABO, Lewis, and P blood group systems, Advances in Human Genetics. (1980) 10, no. 1–136, 379–385, https://doi.org/10.1007/978-1-4615-8288-5_1.
10.1007/978-1-4615-8288-5_1
Google Scholar
6 Flegel W., The genetics of the rhesus blood group system, Blood Transfusion. (2007) 5, no. 2, 50–57, https://doi.org/10.2450/2007.0011-07, 19204754.
10.2450/2007.0011-07
PubMed Google Scholar
7 Hosseini M. B., Genetic characterisation of human ABO blood group variants with a focus on subgroups and hybrid alleles, Vol. 39, 2007, Lund University.
Google Scholar
8 Moon T., An examination of the relationship of ABO blood group and lifespan in a hospitalized population in the Southeastern United States, [Ph.D. Thesis], 2014, Virginia Commonwealth University.
Google Scholar
9 Cooling L., Blood groups in infection and host susceptibility, Clinical Microbiology Reviews. (2015) 28, no. 3, 801–870, https://doi.org/10.1128/cmr.00109-14, 2-s2.0-84933511557.
10.1128/CMR.00109-14
CAS PubMed Web of Science® Google Scholar
10 ISBT, Red cell immunogenetics and blood group terminology, http://www.isbtweb.org/. Archived from the original on 2 February 2022. Retrieved 25 April 2023.2022.
Google Scholar
11 Vuhahula E. A. M., Yahaya J., Morgan E. D., Othieno E., Mollel E., and Mremi A., Frequency and distribution of ABO and Rh blood group systems among blood donors at the Northern Zone Blood Transfusion Center in Kilimanjaro, Tanzania: a retrospective crosssectional study, BMJ Open. (2023) 13, no. 2, e068984, https://doi.org/10.1136/bmjopen-2022-068984, 36787973.
10.1136/bmjopen-2022-068984
PubMed Google Scholar
12 Landsteiner K. and Weiner S., An agglutinable factor in human blood recognized by immune sera for rhesus blood, Proceedings of the Society for Experimental Biology and Medicine. (1940) 43, no. 1, 223–224, https://doi.org/10.3181/00379727-43-11151, 2-s2.0-84964093882.
10.3181/00379727-43-11151
CAS Google Scholar
13 Westhoff C. M., The Rh blood group system in review: a new face for the next decade, Transfusion. (2004) 44, no. 11, 1663–1673, https://doi.org/10.1111/j.0041-1132.2004.04237.x, 2-s2.0-7244228186, 15504174.
10.1111/j.0041-1132.2004.04237.x
CAS PubMed Web of Science® Google Scholar
14 Pratima V., Shraddha S., and Akhilesh K., Prevalence of hemoglobin variants, ABO and rhesus blood groups in Northern Uttar Pradesh, India, Biomedical Research. (2013) 24, 377–382.
Google Scholar
15 Tesfaye K., Petros Y., and Andargie M., Frequency distribution of ABO and Rh (D) blood group alleles in Silte Zone, Ethiopia, The Egyptian Journal of Medical Human Genetics. (2015) 16, no. 1, 71–76, https://doi.org/10.1016/j.ejmhg.2014.09.002, 2-s2.0-84920663592.
10.1016/j.ejmhg.2014.09.002
Google Scholar
16 Bates I. and Owusu-Ofori S., Blood Transfusion, Manson’s Tropical Diseases, 2009, 229–234, https://doi.org/10.1016/B978-1-4160-4470-3.50018-5.
10.1016/B978-1-4160-4470-3.50018-5
Google Scholar
17 IBM Corp, IBM SPSS Statistics for Windows, Version 27.0, 2020, IBM Corp, Armonk, NY, https://www.ibm.com/support/pages/how-cite-ibm-spss-statistics-or-earlier-versions-spss.
Google Scholar
18 R Core Team, R: A language and environment for statistical computing, 2016, R Foundation for Statistical Computing, Vienna, Austria, https://www.R-project.org/.
Google Scholar
19 Alem A. Z., Yeshaw Y., Kebede S. A., Liyew A. M., Tesema G. A., Agegnehu C. D., and Teshale A. B., Spatial distribution and determinants of early marriage among married women in Ethiopia: a spatial and multilevel analysis, BMC Women′s Health. (2020) 20, no. 1, 1–3, https://doi.org/10.1186/s12905-020-01070-x.
10.1186/s12905-020-01070-x
PubMed Web of Science® Google Scholar
20 Ngo N. V., Pemunta N. V., Basil N., Fokunang E. T., Mbong S. E., Ezra K., Che H. N., and Umbugadu E. S., Reproductive health policy Saga: restrictive abortion laws in low- and middle-income countries (LMICs), unnecessary cause of maternal mortality, Health Care for Women International. (2024) 45, no. 1, 5–23, https://doi.org/10.1080/07399332.2021.1994971, 34726567.
10.1080/07399332.2021.1994971
PubMed Web of Science® Google Scholar
21 Meitei S. Y., Asghar M., Achoubi N. D., Murry B., Saraswathy K. N., and Sachdeva M. P., Distribution of ABO and Rh(D) blood groups among four populations in Manipur, North East India, Anthropological Notebooks. (2010) 16, no. 2, 19–28.
Web of Science® Google Scholar
22 Agrawal A., Tiwari A. K., Mehta N., Bhattacharya P., Wankhede R., Tulsiani S., and Kamath S., ABO and rh (D) group distribution and gene frequency; the first multicentric study in India, Asian Journal of Transfusion Science. (2014) 8, no. 2, 121–125, https://doi.org/10.4103/0973-6247.137452, 2-s2.0-84905385575, 25161353.
10.4103/0973-6247.137452
PubMed Google Scholar
23 Browne A., Kinsella A., Keogh M., Morris K., and Field S., A snapshot of ABO, RH, and JK blood group systems in modern Ireland, Health Science Reports. (2021) 4, no. 2, e292, https://doi.org/10.1002/hsr2.292, 34136655.
10.1002/hsr2.292
PubMed Web of Science® Google Scholar
24 Woldu B., Melku M., Shiferaw E., Biadgo B., Abebe M., and Gelaw Y., Phenotype, allele and genotype frequency of ABO and rhesus D blood groups of blood donors at the North Gondar District Blood Bank, Northwest Ethiopia, Journal of Blood Medicine. (2022) Volume 13, 11–19, https://doi.org/10.2147/JBM.S346904, 35023982.
10.2147/JBM.S346904
CAS PubMed Web of Science® Google Scholar
25 Thakur S. K., Singh S., Negi D. K., and Sinha A. K., Phenotype, allele and genotype frequency distribution of ABO and Rh(D) blood group among blood donors attending regional blood transfusion centre in Delhi, India, Bioinformation. (2023) 19, no. 4, 385–391, https://doi.org/10.6026/97320630019385, 37822811.
10.6026/97320630019385
PubMed Web of Science® Google Scholar
26 Hosoi E., Biological and clinical aspects of ABO blood group system, The Journal of Medical Investigation. (2008) 55, no. 3-4, 174–182, https://doi.org/10.2152/jmi.55.174, 18797129.
10.2152/jmi.55.174
PubMed Google Scholar
27 Farhud D. D. and Yeganeh M. Z., A brief history of human blood groups, Iranian Journal of Public Health. (2013) 42, no. 1, 1–6, 23514954.
PubMed Web of Science® Google Scholar
28 Ségurel L., Thompson E. E., Flutre T., Lovstad J., Venkat A., Margulis S. W., Moyse J., Ross S., Gamble K., Sella G., and Ober C., The ABO blood group is a trans-species polymorphism in primates, Proceedings of the National Academy of Sciences. (2012) 109, no. 45, 18493–18498.
10.1073/pnas.1210603109
CAS PubMed Web of Science® Google Scholar
29 Yamamoto F., Molecular genetics and genomics of the ABO blood group system, Annals of Blood. (2021) 6, https://doi.org/10.21037/aob-20-71.
10.21037/aob-20-71
Google Scholar
30 Lalueza-Fox C., Gigli E., de la Rasilla M., Fortea J., Rosas A., Bertranpetit J., and Krause J., Genetic characterization of the ABO blood group in Neandertals, BMC Evolutionary Biology. (2008) 8, no. 1, https://doi.org/10.1186/1471-2148-8-342, 2-s2.0-58649087364, 19108732.
10.1186/1471-2148-8-342
PubMed Web of Science® Google Scholar
31 Patidar G. K. and Dhiman Y., Distribution of ABO and Rh (D) blood groups in India: a systematic review, ISBT Science Series. (2021) 16, no. 1, 37–48, https://doi.org/10.1111/voxs.12576.
10.1111/voxs.12576
Google Scholar
32 At P. and Suksawat S., Prevalence of Rh negative pregnant women who attended the antenatal clinic and delivered in Rajavithi Hospital: 2000-2005, Journal of the Medical Association of Thailand. (2007) 90, no. 8, 1491–1494.
PubMed Google Scholar
33 Hackett W. E. R. and Dawson G. W. P., The distribution of the ABO and simple rhesus (D) blood groups in the Republic of Ireland from a sample of 1 in 37 of the adult population, Irish Journal of Medical Science. (1958) 6, no. 387, 99–109, https://doi.org/10.1007/BF02951249, 2-s2.0-42449128531.
10.1007/BF02951249
Google Scholar
34 Theobald G. W., Textbook of obstetrics, British Medical Journal. (1955) 2, no. 4951, https://doi.org/10.1136/bmj.2.4951.1312-b.
10.1136/bmj.2.4951.1312-b
Google Scholar
35 Levine P., Katzin E. M., and Burnham L., Isoimmunization in pregnancy, JAMA. (1941) 116, no. 9, 825–827, https://doi.org/10.1001/jama.1941.02820090025006, 2-s2.0-84942947912.
10.1001/jama.1941.02820090025006
Web of Science® Google Scholar
36 Bowman J. M., The prevention of Rh immunization, Transfusion Medicine Reviews. (1988) 2, no. 3, 129–150, https://doi.org/10.1016/s0887-7963(88)70039-5, 2-s2.0-0024068480, 2856526.
10.1016/S0887-7963(88)70039-5
CAS PubMed Google Scholar
37 Hauwanga E., Investigating Foetal Maternal Haemorrhage in Stillbirths, Windhoek Central Hospital, Namibia, 2021, Doctoral dissertation, Namibia University of Science and Technology, https://ir.nust.na/server/api/core/bitstreams/30a3809c-611d-486e-80f9-9364b0812489/content.
Google Scholar
38 Schellong G., Sandmann G., Fischer K., and Poschmann A., Haemolytic disease of the new-born by blood-factor incompatibility other than Rh (d) and ABO (author′s transl), Deutsche Medizinische Wochenschrift (1946). (1976) 101, no. 44, 1591–1597, https://doi.org/10.1055/s-0028-1104308, 2-s2.0-0017145588.
10.1055/s-0028-1104308
CAS PubMed Google Scholar
39 Cullen C. L., Erythroblastosis fetalis produced by Kell immunization: dental findings, Pediatric Dentistry. (1990) 12, no. 6, 393–396, 2087415.
CAS PubMed Google Scholar
40 Stark A. E., Pseudo-random mating with multiple alleles, Twin Research and Human Genetics. (2021) 24, no. 4, 200–203, https://doi.org/10.1017/thg.2021.35, 34526157.
10.1017/thg.2021.35
PubMed Web of Science® Google Scholar
41 Saitou N. and Yamamoto F., Evolution of primate ABO blood group genes and their homologous genes, Molecular Biology and Evolution. (1997) 14, no. 4, 399–411, https://doi.org/10.1093/oxfordjournals.molbev.a025776, 2-s2.0-0030930981, 9100370.
10.1093/oxfordjournals.molbev.a025776
CAS PubMed Web of Science® Google Scholar

All articles

The Allelic and Phenotypic Frequencies of the ABO and Rh Blood Types in Pregnant Women in Addis Ababa, Ethiopia

Abstract

1. Introduction