Journal of Neonatal Biology

Role of Maternal ABO Blood Type on Adverse Obstetric Outcomes

Kailey C. Shine¹, Danielle McGinnis¹, Danielle Iben¹, Emily Holthaus², Marim Zoma¹, Kim Baran³, Phillip J. DeChristopher⁴, Loretto Glynn⁵ and Jonathan K. Muraskas^{3* 1}Loyola University Stritch School of Medicine, Maywood, Illinois, United States of America
²Department of Maternal Fetal Medicine, Loyola University Medical Center, Maywood, Illinois, United States of America
³Department of Neonatology, Loyola University Medical Center, Maywood, Illinois, United States of America
⁴Department of Pathology, Loyola University Medical Center, Maywood, Illinois, United States of America
⁵Department of Surgery, New York University Langone Health, New York, United States of America
^*Correspondence: Jonathan K. Muraskas, Department of Maternal Fetal Medicine, Loyola University Medical Center, Maywood, Illinois, United States of America, Email:

Received: 20-May-2025, Manuscript No. JNB-25-28971; Editor assigned: 22-May-2025, Pre QC No. JNB-25-28971 (PQ); Reviewed: 05-Jun-2025, QC No. JNB-25-28971; Revised: 12-Jun-2025, Manuscript No. JNB-25-28971 (R); Published: 19-Jun-2025, DOI: 10.35248/2167-0897.25.14.473

Abbreviations

BMI: Body Mass Index; FGR: Fetal Growth Restriction; PROM: Prolonged Rupture Of Membranes; PPROM: Preterm Prelabor Rupture of Membranes; GDM: Gestational Diabetes Mellitus; EMR: Electronic Medical Record; gHTN: Gestational Hypertension

Introduction

ABO blood groups have been associated with various pathologies, including venous thromboembolism, coronary heart disease, neoplastic processes, and most recently COVID-19, in non-pregnant individuals [1-3]. Non O group blood types have shown to have increased VonWillebrand Factor levels, leading to hypercoagulable states [4]. A, B, and AB blood groups contain antigens on both the surface of the red blood cell, as well as at the endothelial level. Blood group O however contains no such antigens. The association between maternal blood type on adverse obstetrical outcomes in both the neonate and mother have been studied, but a consensus on the effect of maternal blood type has yet to be found [5-12]. Some studies have found an increased risk of preeclampsia in AB type mothers, while other studies have found no association between maternal blood type and preeclampsia [7-12]. A similar pattern holds true for Gestational Diabetes Mellitus (GDM), with conflicting findings of the risk of GDM in AB and non-AB type mothers [13-15]. This study aims to gain a better understanding of negative obstetric outcomes associated with maternal AB blood type, including prematurity, quantitative blood loss, presence of Category 2 or 3 tracing, clinical chorioamnionitis, Fetal Growth Restriction (FGR), stillbirth, Prolonged Rupture Of Membranes (PROM), Preterm Prelabor Rupture of Membranes (PPROM), indications for cesarean section, placental pathologies, maternal diabetes, hypertensive disorders of pregnancy, and maternal medical history including hypertensive disorders of pregnancy, thrombophilia, bleeding disorder, venous thromboembolism, seizure disorder, cholestasis of pregnancy, and COVID-19 infection. Category tracings are defined by the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD) to classify fetal heart rate patterns during labor.

Materials and Methods

This retrospective study was conducted in the Department of Neonatology at Loyola University Medical Center. Following approval by the university’s Institutional Review Board, delivery records were obtained from the Electronic Medical Record (EMR) for a total review of 3,263 deliveries occurring between January 1, 2020 and December 31, 2022. Some variables were autofilled from nurse-entered data into the EMR during the delivery encounter (blood type, maternal age, BMI, gestational age at delivery, quantitative blood loss, mode of delivery, presence of Category 2 or 3 tracing, infant birth weight, NICU transfer, Apgar scores, and both arterial and venous cord gas values). Missing data were obtained through chart review, including maternal gravida and para numbers, clinical chorioamnionitis diagnosis, PROM, PPROM, fetal growth restriction, stillbirth, indications for delivery and cesarean section, hypertensive disorders of pregnancy, and medical history including chronic hypertension, gestational and pre-gestational diabetes, thromobophilia, bleeding disorder, venous thromboembolism, seizure disorder, cholestasis of pregnancy, and COVID-19 infection during pregnancy or at delivery.

Criteria for inclusion in this study was a delivery of any gestational age between the dates January 1, 2020 and December 31, 2022, and documentation of maternal ABO blood type. Pregnant individuals under the age of 18 were excluded from this study.

Clinical chorioamnionitis, gestational hypertension, preeclampsia, preeclampsia with severe features, chronic hypertension, chronic hypertension with superimposed preeclampsia with/without severe features, PROM, PPROM, and intrauterine growth restriction were defined as documented by medical personal in the maternal chart either during prenatal visits or at delivery. Gestational Diabetes Type 1 is defined as gestational diabetes controlled by diet. Gestational Diabetes Type 2 is defined as gestational diabetes controlled by medication.

Statistical methods

Comparisons between maternal blood type AB vs. all other blood types (group containing blood types A, B, and O) were completed using Student’s t-tests, Mann Whitney U tests, Pearson’s chi-square tests, or Fisher’s Exact tests as statistically appropriate. Comparisons between the 4 individual blood types (AB, A, B, O) were completed using ANOVA, Pearson’s chi-square tests, or Kruskal-Wallace tests as statistically appropriate. Post-hoc multivariate logistic regression was used to examine associations of interest identified on bivariate analysis.

Results

A total of 3263 deliveries were reviewed from between January 1, 2020 and December 31, 2022. Of these, 113 patients had blood type AB and 3150 had other blood types (1015 type A, 463 type B, 1672 type O). Patients with blood type AB had statistically higher age than other blood types (31.0 ± 5.2 vs. 29.9 ± 6.1, p=0.046) and lower BMI (31.2 [interquartile range 7] vs. 33 [IQR 9.5], p=0.009) (Table 1). There were no differences in nulliparity, gestational age at delivery, chronic hypertension, gestational diabetes, cholestasis of pregnancy, quantitative blood loss, postpartum hemorrhage, clinical chorioamnionitis, fetal growth restriction, stillbirth, Category 2 or 3 tracing, or mode of delivery. In addition, there were no differences in blood type AB vs. others in rates of thrombophilia, bleeding disorder, maternal heart disease, psychiatric history, seizure disorder, autoimmune disorder, COVID-19 infection at delivery, COVID-19 infection during pregnancy, venous thromboembolism, or prolonged rupture of membranes.

Table 1: Maternal characteristics and outcomes by blood type AB vs. others.

Of the 3263 deliveries, 283 were Rh positive, and 2980 were Rh negative. Patients with Rh positive blood had statistically higher age than Rh negative patients (31.0 ± 5.8 vs. 29.8 ± 6.1, p=0.002) and lower incidence of cholestasis of pregnancy (8 (0.028%)) vs. 31 (0.010%), p=0.017). There was no difference in BMI, nulliparity, gestational age at delivery, chronic hypertension, hypertensive disorder of pregnancy, diabetes diagnosis, venous thromboembolism, quantitative blood loss, postpartum hemorrhage, clinical chorioamnionitis, fetal growth restriction, stillbirth, category 2 or 3 tracing, or mode of delivery. In addition, there were no differences in Rh positive blood type vs. Rh negative blood type in rates of preterm prelabor rupture of membranes, prolonged rupture of membranes, COVID-19 infection in pregnancy, or COVID-19 infection at delivery.

Patients with blood type AB had a gestational hypertension rate of 14% compared to 9% in other blood types (p=0.059) (Table 1). Using Odds Ratios (ORs) to measure the strength of association and 95% confidence intervals (CIs) to indicate precision, this association was further explored in multivariate logistic regression for prediction of gestational hypertension, which showed a statistically significant association for blood type AB vs. other (p=0.032, OR 1.91 (95% CI 1.06–3.43)) when controlling for age (p=0.074, OR 0.98 (95% CI 0.96–1.00), BMI (p<0.001, OR 1.05 (1.04–1.07)), and gestational age (p=0.041, OR 1.06 (1.00–1.11)) (Table 1). However, patients with blood type AB had a preeclampsia and chronic hypertension with superimposed preeclampsia rate of 3.6% compared to 8.9% in other blood types (p=0.05) (Table 1). This, too, was further explored in multivariate logistic regression for prediction of preeclampsia and superimposed preeclampsia, which did not show a statistically significant association for blood type AB vs. other (p=0.089, OR 0.36 (95% CI 0.11–1.17)), when controlling for age (p=0.59, OR 0.99 (0.97–1.02)), BMI (p<0.001, OR 1.06 (1.05–1.08)), and gestational age (p<0.001, OR 0.88 (0.86–0.91)) (Table 2). A third multivariate logistic regression model on any hypertensive disorder of pregnancy (including gestational hypertension, preeclampsia with or without severe feature, eclampsia, and chronic hypertension with superimposed preeclampsia) did not show a statistically significant association for blood type AB vs. other (p=0.65, OR 1.13 (95% CI 0.66–1.95)) when controlling for age, BMI, and gestational age (Table 2).

Table 2: Logistic regression models for hypertensive disorders of pregnancy.

BMI was shown to have a statistically significant association for gestational hypertension (p<0.001, OR 1.05 (95% CI 1.04–1.07)) when controlling for age (p=0.074, OR 0.98 (95% CI 0.96–1.00)), gestational age (p=0.041, OR 1.06 (1.00–1.11)), and blood type AB vs. other (p=0.032, OR 1.91 (95% CI 1.06–3.43)). BMI was also shown to have a statistically significant association for preeclampsia and chronic hypertension with superimposed preeclampsia (p<0.001, OR 1.06 (1.05–1.08)), when controlling for age (p=0.59, OR 0.99 (0.97–1.02)), gestational age (p<0.001, OR 0.88 (0.86–0.91)), and blood type AB vs. other (p=0.089, OR 0.36 (95% CI 0.11–1.17)). Lastly, BMI had a statistically significant association for any hypertensive disorder of pregnancy (p<0.001, OR 1.067 (1.05–1.08)) when controlling for age, gestational age, and blood type AB (Table 2).

Any hypertensive disorder of pregnancy includes gestational hypertension, preeclampsia with or without severe features, eclampsia, and chronic hypertension with superimposed preeclampsia with or without severe features.

Discussion

Human blood groups are divided into four main categories: Type A, B, AB, and O. In the United States, 44% of the population are blood type O, 42% are type A, 10% are type B, and 4% are type AB [16]. These categories are determined based on carbohydrate antigens present on the red blood cell surface. Individuals with blood type AB have A and B antigens on their red blood cell surface, type A have A antigens, type B have B antigens, and type O do not have a corresponding antigen expressed on their red blood cell surface. Each blood type also has corresponding IgG antibodies (isoagglutinins): Type A blood has anti-B, type B blood has anti-A, type O blood has anti-A and anti-B, and type AB blood does not express anti-A or anti-B isoagglutinins.

IgG immunoglobulins passively transfer from the pregnant patient to the fetus through the placenta and isoagglutinins are directly involved in antigen-antibody reactions both intravascularly and at the endothelial level. The isoagglutinin hypothesis was put forth in a previous study by Habeeb, et al., which showed an increased mortality in type AB neonates. This association was attributed to gut injury either from transfused type O blood containing anti-A and anti-B isoagglutinins, or maternal transfer across the placenta [17]. Multiple other studies have identified an increased disease risk in specific blood types, however the exact role of isoagglutinins have yet be identified.

Based off previous findings correlating type AB blood with an increase in multiple disease states, we hypothesized that pregnant patients with type AB blood would be at increased risk of various negative obstetric outcomes. While type AB blood was not correlated with most negative obstetrical outcomes in out retrospective study, upon initial evaluation our data suggests that pregnant patients with type AB blood are at a higher risk of developing gestational hypertension. However, this is likely due to random chance given that there are no associations when examining other categories of hypertensive disorders of pregnancy, including preeclampsia with or without severe features, eclampsia, and chronic hypertension with superimposed preeclampsia with or without severe features when controlling for age, BMI, and gestational age. While our study does contradict previous research evaluating preeclampsia and maternal blood type by Reisig, et al., the hypertensive disorders of pregnancy are thought to be of the same disease process [12].

A potential positive relationship between maternal AB blood type and gestational hypertension may exist and possible pathophysiology can be attributed to maternal A and B antigens at the placental endothelial and vascular level. However, due to the lack of significant findings in other hypertensive disorders of pregnancy, maternal blood should not be used independently as a reliable indication of potential obstetrical outcomes or to identify high-risk mothers.

Our study adds to the growing pool of research investigating blood type and maternal and neonatal disease. A consensus regarding the role of maternal blood type on outcomes such as pre-eclampsia and GDM has been debated in multiple papers. Recent research by Li, et al. and Rom, et al. found a higher incidence of pre-eclampsia in type AB women and a lower risk of developing GDM in type AB women respectively, while our research revealed no associations [11, 15]. These conflicting data sets emphasize the importance of not over utilizing maternal blood type as an indicator for increased screening or surveillance in pregnant women.

Previous studies have shown a pro-inflammatory and prothrombotic state in Type AB blood [2, 18]. Type AB blood has been implicated in increased rates of venous thromboembolism, chronic heart disease, gastric, pancreatic, skin, ovarian, and lung cancers, and FV Leiden [2, 8, 19]. Obesity has a large inflammatory component, including increased pro-inflammatory proteins and decreasing immune system reactivity [20].

One could hypothesize that participants with AB blood would have a higher reported BMI, however our data showed the opposite correlation. Type AB patients had a statistically significant lower BMI than other blood types. This points to other possible inflammatory processes aside from blood type in the pathogenesis of obesity and metabolic syndromes.

The relationship between BMI and hypertensive disorders of pregnancy has been well studied. Our data supports previous studies identifying an increased risk of early and late-onset hypertensive disorders of pregnancy in pregnant patients with increasing BMI [21, 22]. The current pathology of this disease process involve metabolic factors associated with higher BMI’s such as insulin resistance, hyperinsulinism, and increased levels of pro-inflammatory markers such as c reactive protein, TNF-α, and IL-6 [22].

Limitations to our study include a retrospective single-center study. Most data, including FGR, clinical chorioamnionitis, category tracings, and hypertensive disorders of pregnancy, were recorded as documented in the patient’s chart from various medical professionals including physicians and nurses. We yielded one new statistically significant finding of interest, however because only gHTN and no other hypertensive disorder of pregnancy had similar results, we concluded this was due to a type 1 error. Strengths of our study include a large sample population and breakdown of blood phenotype being similar to that of the general population of the United States.

Future directions could pertain to neonatal blood type and its relationship with maternal and neonatal outcomes, as well as blood type in relation to chorioamnionitis as diagnosed by pathology. Further research with additional perinatal measures is warranted to explore the potential influence of both maternal and neonatal blood type on maternal and neonatal health. With this in mind, physicians should be aware of the limitations of using maternal blood type to identity high risk mothers or potential negative obstetric outcomes for both mothers or neonates.

Conclusion

The relationship between ABO blood type and adult disease states, such as various cancers, coagulopathies, COVID-19, and some endocrine disorders has been well established. The relationship between maternal ABO blood type and adverse obstetrical outcomes however has not been as thoroughly studied. This retrospective chart review found a potential positive relationship between maternal AB blood type and gestational hypertension when controlling for age, BMI, and gestational age. Although out results may be limited due to sample size, the lack of similar significant findings for other hypertensive disorders of pregnancy leads us to believe this significant finding between maternal blood type AB and gestation hypertension might be due to random chance. With this in mind, we do not recommend that maternal blood type be used as a reliable indication of potential obstetrical outcomes or to identify high-risk mothers.

Acknowledgements

This study was presented as a platform oral presentation at The Central Association of Obstetrics and Gynecologists 90th annual meeting, in Nashville, Tennessee on October 28, 2023. This study was also presented as a poster presentation at Loyola Health Sciences St. Albert’s Day in Maywood, IL on October 26, 2023, and the 2024 Asian Pacific American Medical Student (APAMSA) National Conference in Las Vegas, Nevada on March 1, 2024.

Disclosure Statement

The authors of this manuscript have no sources of financial support of the study, including provision of supplies or services from a commercial organization. In addition, no funding was received for this work from any organizations. We have no competing interests to disclose.

References

1. Zietz M, Zucker J, Tatonetti NP. Associations between blood type and COVID-19 infection, intubation, and death. Nat Commun. 2020;11(1):5761.

   [Crossref] [Google Scholar] [PubMed]

2. Liumbruno GM, Franchini M. Beyond immunohaematology: The role of the ABO blood group in human diseases. Blood Transfus. 2013;11(4):491-499.

   [Google Scholar] [PubMed]

3. Abegaz SB. Human ABO blood groups and their associations with different diseases. Biomed Res Int. 2021;2021:6629060.

   [Crossref] [Google Scholar] [PubMed]

4. Ward SE, O’Sullivan JM, O’Donnell JS. The relationship between ABO blood group, von Willebrand factor, and primary hemostasis. Blood. 2020;136(25):2864-2874.

   [Crossref] [Google Scholar] [PubMed]

5. 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(3):264-271.

   [Crossref] [Google Scholar] [PubMed]

6. Phaloprakarn C, Tangjitgamol S. Maternal ABO blood group and adverse pregnancy outcomes. J Perinatol. 2013;33(2):107-111.

   [Crossref] [Google Scholar] [PubMed]

7. Mital P, Gupta D, Benwal DK, 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(12):3445-3449.

   [Google Scholar]

8. 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(2):167-173.

   [Crossref] [Google Scholar] [PubMed]

9. Hentschke MR, Caruso FB, Paula LG, Medeiros AK, Gadonski G, Antonello IC, et al. Is there any relationship between ABO/Rh blood group and patients with pre-eclampsia? Pregnancy Hypertens. 2014;4(2):170-173.

   [Crossref] [Google Scholar] [PubMed]

10. Juusela A, Addy S, Nazir M, Gimovsky ML. Perinatal outcomes in preeclampsia stratified by ABO blood group [24L]. OB-GYN. 2020;135:130S.

    [Crossref] [Google Scholar]

11. Li T, Wang Y, Wu L, Ling Z, Li C, Long W, et al. The Association between abo blood group and preeclampsia: A systematic review and meta-analysis. Front Cardiovasc Med. 2021;8:665069.

    [Crossref] [Google Scholar] [PubMed]

12. Reisig RN, Christopher PJD, Habeeb O, Glynn LA, Melone PJ, Muraskas JK. Maternal ABO Phenotype as a Predictive Factor for Pregnancy Complications Related to Prematurity. Int J Gynecol Obstet Neonatal Care. 2016;3(3):51-54.

    [Google Scholar]

13. Shimodaira M, Yamasaki T, Nakayama T. The association of maternal ABO blood group with gestational diabetes mellitus in Japanese pregnant women. Diabetes Metab Syndr. 2016;10(2):S102-5.

    [Crossref] [Google Scholar] [PubMed]

14. Kırlangıç MM, Eraslan Å?ahin M. Assessment of the roles of ABO blood types and Rh factors in gestational diabetes mellitus. Perinat J. 2022;30(1):38-42.

    [Crossref] [Google Scholar]

15. Rom E, Yogev M, Sela N, Jehassi A, Romano S, Salim R. The association between ABO blood groups and gestational diabetes mellitus: A retrospective population-based cohort study. J Matern Fetal Neonatal Med. 2025;35(25):7065-7069.

    [Crossref] [Google Scholar] [PubMed]

16. Reid ME, Mohandas N. Red blood cell blood group antigens: Structure and function. Semin Hematol. 2004;41(2):93-117.

    [Crossref] [Google Scholar] [PubMed]

17. Thomson T, Habeeb O, DeChristopher PJ, Glynn L, Yong S, Muraskas J. Decreased survival in necrotizing enterocolitis is significantly associated with neonatal and maternal blood group: The AB isoagglutinin hypothesis. J Perinatol. 2012;32(8):626-630.

    [Crossref] [Google Scholar] [PubMed]

18. Lai A, Jeske W, Habeeb O, Mooney S, Levin S, Christopher PJD, et al. ABO blood group and procoagulant factors: The hypercoagulation hypothesis ABO and procoagulant factors. Pediatr Res. 2019;86(3):316-322.

    [Crossref] [Google Scholar] [PubMed]

19. Franchini M, Mannucci PM. ABO blood group and thrombotic vascular disease. Thromb Haemost. 2014;112(6):1103-1109.

    [Crossref] [Google Scholar] [PubMed]

20. Heredia FP de, Gómez-Martínez S, Marcos A. Obesity, inflammation and the immune system. Proc Nutr Soc. 2012;71(2):332-338.

    [Crossref] [Google Scholar] [PubMed]

21. Bicocca MJ, Mendez-Figueroa H, Chauhan SP, Sibai BM. Maternal obesity and the risk of early-onset and late-onset hypertensive disorders of pregnancy. OB-GYN. 2020;136(1):118.

    [Crossref] [Google Scholar] [PubMed]

22. Bohiltea RE, Zugravu CA, Nemescu D, Turcan N, Paulet FP, Gherghiceanu F, et al. Impact of obesity on the prognosis of hypertensive disorders in pregnancy. Exp Ther Med. 2020;20(3):2423-2428.

    [Google Scholar] [PubMed]