Medical and Dental Consultantsí Association of Nigeria
Home - About us - Editorial board - Search - Ahead of print - Current issue - Archives - Submit article - Instructions - Subscribe - Advertise - Contacts - Login 
  Users Online: 756   Home Print this page Email this page Small font sizeDefault font sizeIncrease font size

  Table of Contents 
Year : 2020  |  Volume : 23  |  Issue : 5  |  Page : 729-733

ABO blood group as a biomarker of preeclampsia among antenatal clinic attendees in Nigeria

1 Department of Haematology and Immunology, College of Medicine, University of Nigeria/University of Nigeria Teaching Hospital, Ituku-Ozalla Campus, Enugu, Nigeria State, Nigeria
2 Department of Haematology and Immunology, Chukwuemeka Odumegwu Ojukwu University, Awka, Anambra State, Nigeria
3 Department of Obstetrics and Gynaecology, College of Medicine, University of Nigeria/University of Nigeria Teaching Hospital, Ituku-Ozalla Campus, Enugu, Nigeria State, Nigeria

Date of Submission24-Jan-2019
Date of Acceptance10-Feb-2020
Date of Web Publication4-May-2020

Correspondence Address:
Dr. A O Ugwu
Department of Haematology and Immunology, College of Medicine, University of Nigeria/University of Nigeria Teaching Hospital, Ituku-Ozalla Campus, Enugu State. PMB 01129. Postal Code 400001
Login to access the Email id

Source of Support: None, Conflict of Interest: None

DOI: 10.4103/njcp.njcp_48_19

Rights and Permissions

Background: The clinical application of the ABO blood group is not limited to transfusion medicine but extends to other aspects of medicine. Its impact on preeclampsia is controversial. Aim: To determine the association of ABO blood group type with preeclampsia. Subjects and Methods: This was a cross-sectional analytical study of 66 women with preeclampsia and 81 apparently healthy women controls carried out in a tertiary health institution. The case and control groups were consecutively recruited during antenatal clinic visits and matched for age, parity, and gestational age. Data on demographics and the ABO blood group of the two groups of individuals were obtained. The analysis was both descriptive and inferential using the statistical package for social sciences (SPSS) version 21 (Chicago Il, USA). A P value of <0.05 was considered statistically significant. Results: The mean age of the participants was 30.6 (4.9), 95% CI: 27.76–33.95. The majority of the women were ≤40 years (98.5%) and multigravidae constituted 81.8%. Forty-six (69.7%) women with preeclampsia had blood group O and 20 (30.3%) had a non-O blood group. Forty-nine (60.5%) of the controls had blood group O and 32 (39.5%) had a non-O blood group. The observed difference was not statistically significant (OR 1.50; 95% CI: 0.75–3.0; P = 0.26). The odds ratio for developing preeclampsia was 0.83 (95% CI: 0.37–1.91; P = 0.67) for the primigravidae. The non-O blood groups were more likely to present with symptoms than the O group (P < 0.01). Twenty-six (39.4%) women with preeclampsia had a mild disease while 40 (60.6%) had severe disease. Conclusion: Women with non-O blood groups are not at increased risk of developing preeclampsia but are more likely to be symptomatic than the O group.

Keywords: ABO blood group, preeclampsia, severe hypertension, symptomatic

How to cite this article:
Okoye H C, Efobi C C, Ugwu A O, Ugwu E O, Nwagha T U. ABO blood group as a biomarker of preeclampsia among antenatal clinic attendees in Nigeria. Niger J Clin Pract 2020;23:729-33

How to cite this URL:
Okoye H C, Efobi C C, Ugwu A O, Ugwu E O, Nwagha T U. ABO blood group as a biomarker of preeclampsia among antenatal clinic attendees in Nigeria. Niger J Clin Pract [serial online] 2020 [cited 2021 Mar 5];23:729-33. Available from:

   Introduction Top

Antigens of the ABO blood group are oligosaccharides found on endothelial cells, epithelial cells, and red cells.[1] The A and B alleles encode unique glycosyltransferases that add N-acetylgalactosamine and D-galactose to the H substance, this H substance is then converted into A- or B-antigens, respectively.

The clinical application of the ABO blood group is not limited to transfusion medicine but extends to other aspects of medicine. It has been found to be associated with several disease conditions like cardiovascular diseases, cancer, infections, dental malocclusion, and hematological disorders like venous thromboembolism.[2],[3],[4],[5]

Despite several studies on preeclampsia, the etiology is still not clear. Some risk factors thought to predispose to preeclampsia include preexisting hypertension, previous personal history of early-onset preeclampsia, and hypertension as well as a family history of preeclampsia. Preeclampsia is associated with symptoms like headaches, edema, weight gain, visual changes, abdominal pain, dyspnea, nausea, and vomiting. They can present with seizures when severe. The severity of preeclampsia is graded into mild and severe. Mild preeclampsia was taken as blood pressure (BP) of 140–160 mmHg systolic, 90–110 mmHg diastolic, absence of symptoms such as epigastric pain and headaches. Severe preeclampsia has BPs greater than 160 mmHg systolic, diastolic of more than 110 mmHg, thrombocytopenia (<100,000/μL), proteinuria of ≥3+ on two random urine samples.[6],[7]

Over time, several researchers have studied the association of ABO group type with poor pregnancy outcomes like preeclampsia and HELLP syndrome, intrauterine fetal growth restriction (IUGR), venous thromboembolism (VTE), post-partum hemorrhage, and gestational diabetes and there exist some controversies.[8],[9] Several studies have shown a relationship between ABO blood group and preeclampsia with blood group AB women being at higher risk of developing preeclampsia[10],[11],[12] whereas this is disproved by other studies.[13],[14]

There are conflicting findings on the association between preeclampsia and ABO blood groups. Our aim is, therefore, to determine the association between ABO blood group and preeclampsia in our environment. This study will also serve to highlight the need for early follow-up of pregnant women whose blood groups put them at high risk of developing preeclampsia.

   Patients and Methods Top

This was a cross-sectional analytical study carried out at our institution from May to October 2015. A total of 147 consenting pregnant women who attended the antenatal clinic of the hospital were consecutively recruited. They were made up of 66 cases and 81 controls. The cases were women who were diagnosed of preeclampsia defined as a BP of ≥140/90 mmHg, with proteinuria >300 mg/24 h period or ≥2+ dipstick occurring in a pregnant women at a gestational age of 20 weeks or more,[15] whereas, the control group was made up of apparently healthy pregnant women matched for age, parity, and gestational age. Participants were considered to have severe preeclampsia if the systolic BP was >160 mmHg and/or diastolic was >110 mmHg or proteinuria ≥3+ on a dipstick urine sample.

The minimum sample size (n) for this study was calculated using the formula for comparison of proportions according to Kirkwood.[16] Assuming a 30% increase in the incidence of preeclampsia among blood group O women compared to the general population;[17] with an attrition rate of 10% for possible dropouts or losses to follow-up, the minimum sample size for each group was 63 corresponding to 80% statistical power and 5% level of significance.

Prior to recruitment and inclusion into the study, written informed consent was obtained from the women. 3 mL of venous blood was collected from the women for blood group typing. Other parameters such as biodata, the BP at diagnosis (or at the point of recruitment for the controls), degree of proteinuria (using a dipstick) were retrieved from the case notes. With the aid of a pro forma associated symptoms and previous history of hypertension or preeclampsia were equally obtained. Women with incomplete data from case notes and those who had diabetes mellitus, vascular or chronic renal diseases were excluded. Ethical clearance was obtained from the institutional review board of our institution. The procedures followed were in accordance with the ethical standards of the ethical committee on human experimentation and with the Helsinki Declaration of 1975, as revised in 2000 (available at

Statistical analysis was done using the statistical package for social sciences (SPSS) version 21 (Chicago Il, USA). Categorical variables were presented in simple proportion and continuous variables as mean and standard deviation. The results were presented as tables. Chi-square and student t-test were used for comparison of the categorical and continuous variables between groups. Relationships were expressed using the odds ratio and confidence interval. Significance was set at 0.05.

   Results Top

The study flow chart is as shown in [Figure 1]. The demographic characteristics of the two groups including age, gravidity, and parity were similar as shown in [Table 1]. Twenty-six (39.4%) women with preeclampsia had a mild disease while 40 (60.6%) had severe disease.
Figure 1: Study flowchart

Click here to view
Table 1: Demographics of study participants

Click here to view

As shown in [Table 2], 46 (69.7%) of women with preeclampsia had blood group O and 20 (30.3%) had a non-O blood group. Conversely, 49 (60.5%) of the controls had blood group O and 32 (39.5%) have a non-O blood group. The observed difference was not statistically significant (P = 0.639; OR: 1.5; 95% CI: 0.75–3.00).
Table 2: Blood group and severity of preeclampsiaa

Click here to view

Out of the 66 women with preeclampsia, 48 presented with headaches, edema, epigastric pain, blurred vision, breathlessness, vomiting, or seizures. These symptoms were analyzed against the different blood groups. [Table 3] shows that while individual symptoms did not differ significantly between the groups, overall, the non-O blood group was significantly more symptomatic than the O blood group (P < 0.01).
Table 3: Blood group of the women and the associated symptoms at presentationa

Click here to view

[Table 4] shows the distribution of the median values of blood pressure and proteinuria of study participants.
Table 4: Median values of blood pressure and proteinuria of study participants

Click here to view

   Discussion Top

The relationship between the ABO blood group system and several disease entities has been researched by several groups in the past. Previous works have studied the effect of ABO blood group on diseases such as cardiovascular diseases, colorectal cancers, and proneness to bacterial and viral illnesses.[15],[18] Similar studies that compared the relationship between preeclampsia and ABO blood group gave results that are conflicting and controversial.[14]

The incidence of preeclampsia in the developing world such as Nigeria varies widely. It ranges from 1.2% to 6% from the previous works done in Calabar and Sokoto.[14],[19] This underscores the need to find out the risk factors for preeclampsia which leads to maternal and infant morbidity and mortality. The ages of women with preeclampsia are commonly below 40 years and we know that preeclampsia is seen mostly among women who are 35 years and below. Our study showed that the primigravidae have a higher risk of developing preeclampsia and this finding is in keeping with the findings of Jido and Yakasai 2013, who found a higher incidence among nulliparous women than multiparous women.[20],[21] Among those women who had preeclampsia in their previous pregnancies, the risk of having preeclampsia increases from 4.1% in the first pregnancy, to 14.7% in the second pregnancy and then to 31.9% in the third.[20] This may explain why we have a higher incidence of preeclampsia among the multiparous women when compared to the primigravidae. There was no association found between blood groups and preeclampsia from our study as was also reported by a local study in south-west Nigeria.[22] Even though it was not significant, our study showed that women with blood group O were even more at risk of developing preeclampsia. This is similar to the work reported by Elmugabil et al. which was carried out on an African population.[23] On the contrary, a work carried out by Phaloprakarn and Tangjitgamol in Iran showed an association between the ABO blood group and the development of preeclampsia.[24] Likewise, other researchers found a high risk of developing preeclampsia among women with blood group AB,[25],[26],[27] where they proposed careful grouping of antenatal women with great attention given to those women with AB blood group because they have been found to have higher thrombotic events than O blood group. It is worthy to note that all these referenced studies reporting an association between ABO blood group and preeclampsia were carried out on the non-Nigerian population. In our study, only one patient (1.51%) is of the AB blood group as against 750 (7.74%) reported in the Indian study. Even though the frequency may be affected by the limited sample size, the prevalence of AB blood group is known to be lower among Nigerians (3.7%),[28] when compared to the Indians and Scandinavians where the prevalence of AB blood group is reportedly 5–7%.[29] These suggest a possible contributory ethnic/environmental factors to the prevalence of preeclampsia among women with AB blood group.

Although making a diagnosis of preeclampsia requires only blood pressure and proteinuria,[15] some clinical features/symptoms such as headache, blurring of vision, etc., are used to determine severity.[21] The findings from this study show that there is a relationship between the blood group and the development of symptoms associated with preeclampsia. Whereas the non-O blood group was found to be more likely to be symptomatic than the O blood group, the individual symptoms were not significantly associated with any blood group type. The import of this finding will need to be elucidated by further studies. Nevertheless, these associated symptoms may aid early diagnosis and prompt intervention thereby curbing morbidity and mortality resulting from preeclampsia.

Limitations of the study include the fact that the study was conducted in only one center which limits the generalization of the findings to the entire population. Furthermore, the study did not follow up with the women to ascertain the pregnancy outcome. The major strength of this study was in its prospective design with increased accuracy in data collection.

   Conclusion Top

Women with non-O blood groups are not at increased risk of developing preeclampsia. They are however more likely to be symptomatic than the O counterparts which may aid early identification and intervention.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient (s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

   References Top

De Mattos LC. Structural Diversity and biological importance of ABO, H, Lewis and secretor histo-blood group carbohydrates. Rev Bras Hematol Hemoter 2016;38:331-40.  Back to cited text no. 1
Sharma R, Preethi PN, Nagarathna C, Navin HK. Association of ABO blood groups with malocclusion in population of Jaipur, India: A prospective study. Int J Sci Study 2015;2:45-51.  Back to cited text no. 2
Baqir GK, Al-Sulami A, Hamadi SS. Relationship between ABO blood groups and helicobacterpylori infection among patients with dyspepsia. J Virol Microbiol 2016; doi: 10.5171/2015.688370. Available from: [Last accessed 218 Sep 22].  Back to cited text no. 3
Aly R, Yousef A, Elbably O. Association of ABO blood group and risk of breast cancer. J Blood Disorders Transf 2014;5:241-9.  Back to cited text no. 4
Zhang B, He N, Huang Y, Song F, Chen K. ABO blood groups and risk of cancer: A systematic review and meta-analysis. 2014. Asian Pac J Cancer Prev 2014;15:4643-50.  Back to cited text no. 5
Tranquilli AL, Brown MA, Zeeman GG, Dekker G, Sibai B. The definition of severe and early-onset preeclampsia. Statements from the international society for the study of hypertension in pregnancy (ISSHP). Pregnancy Hypertens 2013;3:44-7.  Back to cited text no. 6
Ramos JGL, Sass N, Costa SHM. Preeclampsia. Rev Bras Ginecol Obstet 2017;39:496-512.  Back to cited text no. 7
Franchini M, Mengoli C, Lippi G. Relationship between ABO blood group and pregnancy complications: A systematic literature analysis. Blood Transfus 2016;14:441-8.  Back to cited text no. 8
Chauleur C, Cochery-Nouvellon E, Mercier E, Aya G, Fabbro-Peray P, Mismetti P, et al. Some hemostasis variables at the end of the population distributions are risk factors for severe postpartum hemorrhages. J Thromb Haemost 2008;6:2067-74.  Back to cited text no. 9
Burgess A, Johnson TS, Simanek A, Bell T, Founds S. Maternal ABO blood type and factors associated with preeclampsia subtype. Biol Res Nurs 2019;21:264-71.  Back to cited text no. 10
Hiltunen LM, Laivuori H, Rautanen A, Kaaja R, Kere J, Krusius T, et al. Blood group AB and factor V Leiden as risk factors for pre-eclampsia: A population based nested case-control study. Thromb Res 2009;124:167-73.  Back to cited text no. 11
Avci D, Karagoz H, Ozer O, Esmera K, Bulut K, Aykas F, et al. Are the blood groups of women with preeclampsia a risk factor for the development of hypertension postpartum? Ther Clin Risk Manag 2016:12:617-22.  Back to cited text no. 12
Aghasadeghi F, Saadat M. Association between ABO and Rh blood groups and risk of preeclampsia: A case-control study from. IJMS 2017;5:173-6.  Back to cited text no. 13
Beyazit F, Pek E, Güngör AC, Gencer M, Unsal MA. Effect of maternal ABO blood type on birth weight and preeclampsia. Int J Reprod Contracept Obstet Gynecol 2017;6:2164-7.  Back to cited text no. 14
Report of the National high blood pressure education programmme (NHBPEP) working group on high blood pressure in pregnancy. Am J Obstet Gynecol 2000;183:S1-S22.  Back to cited text no. 15
Kirkwood BR. Calculation of required sample size. In: Kirkwood BR, editor. Essentials of Medical Statistics. 1st ed. Oxford: Blackwell scientific Publications; 1988. p. 191-200.  Back to cited text no. 16
Ugwu EO, Dim CC, Okonkwo CD, Nwankwo TO. Maternal and perinatal outcome of severe pre-eclampsia in Enugu, Nigeria after introduction of Magnesium sulfate. Niger J Clin Pract 2011;14:418-21.  Back to cited text no. 17
[PUBMED]  [Full text]  
Ewald DR, Sumner SC. Blood type biochemistry and human disease. Wiley Interdiscip Rev Syst Biol Med 2016;8:517-35.  Back to cited text no. 18
Singh S, Ahmed EB, Egondu SC, Ikechukwu NE. Hypertensive disorders in pregnancy among pregnant women in a Nigerian Teaching Hospital. Niger Med J 2014;55:384-8.  Back to cited text no. 19
[PUBMED]  [Full text]  
Jido TA, Yakasai IA. Preeclampsia: A review of the evidence. Ann Afr Med 2013;12:75-85.  Back to cited text no. 20
[PUBMED]  [Full text]  
Mayrink J, Souza RT, Feitosa FE, Rocha Filho EA, Leite DF, Vettorazzi J, et al. Incidence and risk factors for Preeclampsia in a cohort of healthy nulliparous pregnant women: A nested case-control study. Sci Rep 2019;9:9517.  Back to cited text no. 21
Ganiyu AO, Ayebatonyo CDM, Abioye OO, Jaye O. Maternal and neonatal outcomes of pre-eclampsia in African black women, South West Nigeria. GJMS 2015;5:674-6.  Back to cited text no. 22
Elmugabil A, Rayis DA, Ahmed MA, Adam I, Gasim GI. O blood group as risk factor for preeclampsia among Sudanese women. Open Access Maced J Med Sci 2016;4:6036.  Back to cited text no. 23
Phaloprakarn C, Tangjitgamol S. Maternal ABO blood group and adverse pregnancy outcomes. J Perinatol 2013;33:107-11.  Back to cited text no. 24
Lee B, Zhang Z, Wikman A, Lindqvist P, Reilly M. ABO and RhD blood groups and gestational hypertensive disorders: A population-based cohort study. BJOG 2012;119:1232-7.  Back to cited text no. 25
Mital P, Gupta D, Benwal DV, Gangwal H, Hooja N, Agarwal S, et al. To find any association of maternal blood group as a risk factor for preeclampsia. Int J Community Med Public Health 2016;3:3445-9.  Back to cited text no. 26
Manjunatha S, Anita K. The relationship between maternal blood group and preeclampsia. Int J Reprod Contracept Obstet Gynecol 2015;4:1749-52.  Back to cited text no. 27
Anifowoshe AT, Owolodun OA, Akinseye KM, Iyiola OA, Oyeyemi BF. Gene frequencies of ABO and Rh groups in Nigeria: A review. Egypt J Med Hum Genet 2017;18:205-10.  Back to cited text no. 28
Agrawal A, Tiwari AK, Mehta N, Bhattacharya P, Ravi Wankhede R, Tulsiani S, et al. ABO and Rh (D) group distribution and gene frequency; the first multicentric study in India. Asian J Transfus Sci 2014;8:121-5.  Back to cited text no. 29
[PUBMED]  [Full text]  


  [Figure 1]

  [Table 1], [Table 2], [Table 3], [Table 4]


    Similar in PUBMED
   Search Pubmed for
   Search in Google Scholar for
 Related articles
    Access Statistics
    Email Alert *
    Add to My List *
* Registration required (free)  

  In this article
   Patients and Methods
    Article Figures
    Article Tables

 Article Access Statistics
    PDF Downloaded80    
    Comments [Add]    

Recommend this journal