ABO and RhD blood groups and gestational hypertensive disorders: a population-based cohort study

The effect of histo-blood group ABO system transferase (BGAT) on pregnancy related outcomes：A Mendelian randomization study

Protein level of Histo-Blood Group ABO System Transferase (BGAT) has been reported to be associated with cardiometabolic diseases. But its effect on pregnancy related outcomes still remains unclear. Here we conducted a two-sample Mendelian randomization (MR) study to ascertain the putative causal roles of protein levels of BGAT in pregnancy related outcomes. Cis-acting protein quantitative trait loci (pQTLs) robustly associated with protein level of BGAT (P < 5 ×10-8) were used as instruments to proxy the BGAT protein level (N = 35,559, data from deCODE), with two additional pQTL datasets from Fenland (N = 10,708) and INTERVAL (N = 3301) used as validation exposures. Ten pregnancy related diseases and complications were selected as outcomes. We observed that a higher protein level of BGAT showed a putative causal effect on venous complications and haemorrhoids in pregnancy (VH) (odds ratio [OR]=1.19, 95% confidence interval [95% CI]=1.12-1.27, colocalization probability=91%), which was validated by using pQTLs from Fenland and INTERVAL. The Mendelian randomization results further showed effects of the BGAT protein on gestational hypertension (GH) (OR=0.97, 95% CI=0.96-0.99), despite little colocalization evidence to support it. Sensitivity analyses, including proteome-wide Mendelian randomization of the cis-acting BGAT pQTLs, showed little evidence of horizontal pleiotropy. Correctively, our study prioritised BGAT as a putative causal protein for venous complications and haemorrhoids in pregnancy. Future epidemiology and clinical studies are needed to investigate whether BGAT can be considered as a drug target to prevent adverse pregnancy outcomes.

Blood Type and Outcomes in Pregnant Women with Placenta Previa

Background

Placenta previa increases the risks of obstetrical complications. Many studies have reported a link between various ABO blood types and pregnancy complications. This study is aimed at describing and comparing the characteristics and outcomes of women with placenta previa by ABO blood type.

Methods

Data for this study was obtained from a retrospective cohort study between January 1, 2014, and June 30, 2019, of all clinically confirmed placenta previa in a university-based tertiary medical center. Both types of A, B, O, AB, and combining O and non-O blood types were compared to the characteristics and outcomes.

Results

1678 participants with placenta previa were included in this study. The highest participants were blood type O with 666 (39.7%), followed by type A with 508 (30.3%) and type B with 395 (23.5%), and the lowest participants were AB with 109 (6.5%). Blood type AB had a higher incidence of antepartum hemorrhage (p = 0.017), predelivery anemia (p = 0.036), and preterm birth (p = 0.015) in placenta previa women. Meanwhile, the incidence of rhesus D positive (97.9% vs. 95.8%, p = 0.012) and twins (5.0% vs. 2.7%, p = 0.011) was higher in the non-O group, and the incidence of neonatal asphyxia (5.9% vs. 9.2%, p = 0.016) was lower in the non-O group.

Conclusion

Type AB blood may be a potential risk factor for women with placenta previa. This finding may help provide any obstetrician to predict the risk of complication for placenta previa women by the ABO blood types.

The impact of maternal ABO blood type on obstetric and perinatal outcomes after frozen embryo transfer

RESEARCH QUESTION

Does the maternal ABO blood type affect obstetric and perinatal outcomes following frozen embryo transfer (FET)?

DESIGN

A retrospective study was performed at a university-affiliated fertility centre, involving women with singleton and twin deliveries conceived by FET. Subjects were divided into four groups based on ABO blood type. The primary end-points were obstetric and perinatal outcomes.

RESULTS

A total of 20,981 women were involved, with 15,830 having singletons and 5151 delivering twins. In singleton pregnancies, women with blood group B had a slight but significantly increased risk of gestational diabetes mellitus compared to women with blood group O (adjusted odds ratio [aOR] 1.16; 95% confidence interval [CI] 1.01-1.34). Furthermore, singletons born to women with the B antigen (blood type B or AB) were more likely to be large for gestational age (LGA) and with macrosomia. In twin pregnancies, blood type AB was related to a decreased risk of hypertensive diseases of pregnancy (aOR 0.58; 95% CI 0.37-0.92), while blood type A was associated with a higher risk of placenta praevia (aOR 2.04; 95% CI 1.15-3.60). When compared with the O blood group, twins from the AB blood group had a lower risk of low birthweight (aOR 0.83; 95% CI 0.71-0.98) but a higher risk of LGA (aOR 1.26; 95% CI 1.05-1.52).

CONCLUSIONS

This study demonstrates that the ABO blood group may influence the obstetric and perinatal outcomes for both singletons and twins. These findings emphasize that patient characteristics could be, at least partly, responsible for adverse maternal and birth outcomes following IVF.

The Association Between ABO Blood Group and Preeclampsia: A Systematic Review and Meta-Analysis

Objective: This meta-analysis comprehensively evaluated the association between ABO blood group and the risk of preeclampsia (PE).

Design: Systematic review and meta-analysis.

Data sources: PubMed, Web of Science, and ScienceDirect databases from their inception to September 23, 2020.

Methods: Pooled odds ratios (ORs) with 95% confidence intervals (CIs) were obtained through random-effects and fixed-effects models according to heterogeneity. Meta-regression analysis was applied to explore the source of heterogeneity. We conducted a subgroup analysis by the publication year, study design, state, and Newcastle-Ottawa Scale (NOS) score. In addition, we calculated the rate of each ABO blood group in PE by total pooled effects.

Results: A total of 12 articles with 714,153 patients were included in our analysis. Compared with people without PE (control group), the O blood group presented a lower risk of PE (OR 0.95, 95% CI 0.93–0.97). The AB (OR 1.46, 95% CI 1.12–1.91) blood group presented a higher risk. However, the total pooled OR and 95% CI for the A (OR 1.02, 95% CI 0.90–1.16) and B (OR 1.02, 95% CI 0.98–1.05) blood groups were not significant. The funnel plot and linear regression equation showed that there was no publication bias for the O, A, or B blood groups (all P > 0.05). However, the funnel plot and linear regression equation for the AB blood group were obviously asymmetric (P < 0.05), and the publication bias persisted even after the trim-and-fill method was applied (P < 0.05). Multivariable meta-regression analysis did not find a specific source of heterogeneity. The A blood group showed an association with early-onset PE (OR 0.53, 95% CI 0.33–0.83), and the other blood groups showed no significant differences. In PE, the rates of the O, A, B, and AB blood groups decreased gradually (0.39, 0.33, 0.19, 0.07).

Conclusion: These findings suggest that pregnant women with AB blood group are more likely to develop PE, and more attention should be paid to AB blood group whose blood pressure is high but not sufficient to diagnose PE.

Systematic Review Registration: Prospero CRD42021227930.

Relationship between ABO blood groups and gestational hypertensive disorders: A protocol for systematic review and meta-analysis

BACKGROUND

The distribution of ABO blood group is related to the incidence of various diseases. Gestational hypertensive disorders (GHD) is one of the most important risk factors during pregnancy, which has certain heredity. It is reported that ABO blood type is associated with the risk of GHD. However, the results are still controversial. In this study, we conducted a systematic review and meta-analysis to clarify the relationship between ABO blood group and GHD.

METHODS

All eligible studies come from Embase, Cochrane Library, Pubmed, Chinese databases SinoMed, Chinese National Knowledge Infrastructure, Chinese Scientific Journals Database, and Wanfang Data. The retrieval time is from the establishment of the database to March 2021. The language will be limited to Chinese and English. The 2 reviewers will be responsible for the selection of the study, the extraction of data, and the evaluation of the quality of the research. Pooled odds ratios (ORs) with 95% confidence intervals (CIs) were used to assess the corresponding associations. Sensitivity analysis, publication bias assessment, and heterogeneity test were performed using STATA 16.0.

RESULTS

The results of this meta-analysis will be published in peer-reviewed journals.

CONCLUSION

This study will provide evidence to support the relationship between ABO blood group and the risk of GHD.

ETHICS AND DISSEMINATION

The private information from individuals will not be published. This systematic review also will not impair endangering participants' rights. Ethical approval is not required. The results may be published in a peer-reviewed journal or disseminated in relevant conferences.

OSF REGISTRATION NUMBER

DOI 10.17605/OSF.IO/3X9YZ.

An agnostic study of associations between ABO and RhD blood group and phenome-wide disease risk

Background

There are multiple known associations between the ABO and RhD blood groups and disease. No systematic population-based studies elucidating associations between a large number of disease categories and blood group have been conducted.

Methods

Using SCANDAT3-S, a comprehensive nationwide blood donation-transfusion database, we modeled outcomes for 1217 disease categories including 70 million person-years of follow-up, accruing from 5.1 million individuals.

Results

We discovered 49 and 1 associations between a disease and ABO and RhD blood groups, respectively, after adjustment for multiple testing. We identified new associations such as a decreased risk of kidney stones and blood group B as compared to blood group O. We also expanded previous knowledge on other associations such as pregnancy-induced hypertension and blood groups A and AB as compared to blood group O and RhD positive as compared to negative.

Conclusions

Our findings generate strong further support for previously known associations, but also indicate new interesting relations.

Funding

Swedish Research Council.

Frequency of ABO Blood Group in Pregnant Women and Its Correlation With Pregnancy-Related Complications

Introduction

The ABO blood group type has been considered an independent risk factor in the occurrence of pregnancy-related complications leading to significant morbidity and mortality in pregnant mothers and neonates. This study aims to determine the maternal ABO blood group and its correlation with pregnancy-related complications.

Methods

We analysed data of 497 pregnant female patients aged between 25 and 40 years who presented with a gestational age of > 14 weeks from June 1, 2020, to November 30, 2020. Patients’ age, parity, gestational age at the first visit, body mass index (BMI) at the first visit, ABO blood group, gestational age at delivery, mode of delivery, birth weight of neonate, and pregnancy-related complications including preeclampsia, gestational diabetes mellitus (GDM), preterm delivery, low birth weight (LBW), and small for gestational age (SGA) infants were evaluated.

Results

The mean age of 497 patients was 27.6 (27.62 ± 3.35) years. Mean BMI was 22.7 (22.7 ± 3.1 kg/m²), parity was 1.85 (1.85 ± 2.3), gestational age at first visit was 23.19 (23.19 ± 3.4) weeks and gestational age at delivery was 37.0 (37.0 ± 2.6) weeks. There were 205 (41.25%) spontaneous vaginal delivery and 292 (58.75%) cesarean sections. The average birth weight of the neonate was 2684.31 ± 622.4 g. Preeclampsia was observed in 107 (21.53%), GDM in 17 (3.42%), and preterm delivery in 154 (30.99%) women. Considering the neonatal outcome, 124 (24.95%) babies had LBW and 49 (9.86%) were SGA. The rate of preeclampsia and GDM was not statistically significant among different blood groups while the rate of preterm delivery, LBW, and SGA was significant among women with different blood groups.

Conclusion

We conclude that the ABO blood group is associated with maternal and neonatal pregnancy-related complications when considering the risk of preterm delivery, LBW, and SGA but not with GDM and preeclampsia. This finding will help clinicians to identify the patients at risk of developing pregnancy-related complications and hence, to take timely and appropriate measures.

Evaluation of maternal rhesus blood type as a risk factor in adverse pregnancy outcomes in Korea: a nationwide health insurance database study

OBJECTIVES

The current study aimed to investigate whether pregnancy outcomes are affected by maternal rhesus (Rh) status by comparing the primigravida pregnancy outcomes of Rh-negative women with those of Rh-positive women.

METHODS

The study data were collected from the Korea National Health Insurance Claims Database and the National Health Screening Program for Infants and Children. In total, 1,664,882 primigravida women who gave birth between January 1, 2007 and December 31, 2014, were enrolled in this study. As the risk and severity of sensitization response increases with each subsequent pregnancy, only primigravida women were enrolled. The patients were divided into 2 groups according to Rh status, and the pregnancy outcomes were compared.

RESULTS

In total, 1,661,320 women in the Rh-positive group and 3,290 in the Rh-negative group were assessed. With regard to adverse pregnancy outcomes, there was no statistically significant difference between the 2 groups in terms of the prevalence of preeclampsia, postpartum hemorrhage, abruptio placenta, placenta previa, and uterine artery embolization. A univariate analysis revealed that none of the adverse pregnancy outcomes were significantly correlated to Rh status (preeclampsia: odds ratio [OR], 1.00, 95% confidence interval [CI], 0.81-1.23; postpartum hemorrhage: OR, 1.10, 95% CI, 0.98-1.24; abruptio placenta: OR, 0.80, 95% CI, 0.46-1.37; and placenta previa: OR, 1.08, 95% CI, 0.78-1.42). The adjusted ORs of postpartum hemorrhage and preterm birth did not significantly differ.

CONCLUSION

Maternal Rh status is not associated with adverse outcomes in primigravida women.

Relationship between ABO blood groups and preeclampsia

OBJECTIVE

To investigate the relationship between ABO blood group and preeclampsia.Methods: A case-control study was conducted, including 230 and 460 women with and without preeclampsia. ABO blood groups were compared and associated factors for preeclampsia were determined.Results: Blood group O was significantly more common in early-onset and less common in late-onset preeclampsia. Regression analysis showed that blood group O decreased the risk of late-onset preeclampsia (aOR 0.63, 95%CI 0.42-0.93) but increased the risk of early-onset preeclampsia (aOR 1.97 95%CI 1.05-3.69).Conclusion: Blood group O decreased the risk of late-onset preeclampsia while it increased the risk of early-onset preeclampsia.

Maternal ABO Blood Type and Factors Associated With Preeclampsia Subtype

BACKGROUND

The pathophysiology of preeclampsia remains unclear. The disorder is heterogeneous, and the pathophysiology may vary by subtype. Identification of relevant biomarkers will help to better elucidate the pathophysiologic basis of each preeclampsia subtype. Blood type may be a biomarker that allows risk identification for preeclampsia.

OBJECTIVE

The purpose of this study was to investigate the associations among maternal ABO blood type and preeclampsia subtype and fetal growth restriction (FGR).

METHOD

Medical records of 126 women with early-onset preeclampsia (≤33 6/7 weeks' gestation), 126 women with late-onset preeclampsia (≥34 0/7 weeks' gestation), and 259 controls who gave birth between January 2012 and June 2016 were retrospectively abstracted from a large suburban tertiary referral center in South Central Pennsylvania for this hospital-based case-control study.

RESULTS

Women with AB blood type had >3 times the odds of late-onset preeclampsia (odds ratio [ OR] = 3.35, 95% confidence interval (CI) = [1.02, 11.05]) compared to those with O blood type. Among women with early-onset preeclampsia, those with B blood type had 5 times the odds of having a growth-restricted fetus than did women with O blood type ( OR = 5.44, 95% CI [1.65, 17.94]).

DISCUSSION

Our findings suggest that AB blood type may be an important risk factor for late-onset preeclampsia and that among women with early-onset preeclampsia, those with B blood type have increased odds of FGR. These findings warrant further study in women and their offspring to identify the pathophysiologic processes that may link ABO blood type, preeclampsia subtype, and FGR.

Placental protein 13: An important biological protein in preeclampsia

Placental protein 13 (PP13), a glycan binding protein predominantly expressed in syncytiotrophoblast, dimeric in nature, lacks N-terminal signal peptide, bypasses the endoplasmic reticulum, and secretes into maternal circulation as exosomes or microvesicles. PP13 has jelly roll fold conformation with conserved carbohydrate recognition domain which specifically binds to β-galactosides of the glycan receptors during placentation. PP13 binds to glycosylated receptors on human erythrocytes and brings about hemagglutination by the property of lectin activity; other functions are immunoregulation and vasodilation during placentation and vascularization. The gene LGALS13 located on 19q13.2 comprising four exons expresses a 32-kDa protein with 139 amino acid residues, PP13. Impaired expression due to mutation in the gene leads to a nonfunctional truncated PP13. The low serum levels predict high risk for the onset of preeclampsia or obstetric complications. Hence, PP13 turned to be an early marker for risk assessment of preeclampsia. The recombinant PP13 and monoclonal antibodies availability help for replenishing PP13 in conditions with low serum levels and for detection and prevention of preeclampsia, respectively.

ABO blood group is a risk factor for coronary artery disease in patients with poor blood pressure control

BACKGROUND

Few studies had examined the role of ABO blood groups on CAD in hypertensive patients with different blood pressure (BP) controls.

METHODS

A total of 2708 patients with primary hypertension (HTN) were consecutively enrolled and underwent coronary angiography (CAG) due to angina-like chest pain. The severity of coronary artery stenosis was assessed by Gensini score (GS). Patients were divided into two groups due to results of CAG: HTN with CAD (n = 2185) and HTN without CAD (n = 523). Poor BP control was defined as systolic BP (SBP) ≥ mean in the study. Multivariable regression analysis was used to determine the potential impact of ABO blood groups on risk of the presence and severity of CAD.

RESULTS

Compared to HTN without CAD group, the percentage of A blood group was statistically higher and O blood group was significantly lower in HTN with CAD group. Moreover, percentage of the angiography-proven CAD was higher in A blood group than that in non-A blood group (p < 0.05). After adjusting for confounding factors, A blood group was independently associated with CAD (odds ratio (OR): 1.422; 95% confidence interval (CI): 1.017-1.987; p = 0.039) and GS (β = 0.055, p = 0.046) in patients with poor BP control.

CONCLUSIONS

A blood group was an independent risk factor for the presence and severity of CAD in hypertensive patients with poor BP control.

Association between ABO and Rh Blood Groups and Risk of Preeclampsia: A Case-Control Study from Iran

AIM:

Preeclampsia (PE) is a major cause of maternal and neonatal morbidity and mortality. There is a genetic component in the development of PE with estimated heritability around 0.47. Several studies have investigated the association between maternal ABO blood groups (OMIM 110300) and risk of PE, with contradictory results have emerged. Considering that there is no study in this filed from Iranian population, the present case-control study was carried out at Shiraz (south-west Iran).

MATERIAL AND METHODS:

In this study 331 women; 121 pregnant with PE and 210 normotensive pregnant women were included. Using blood group O (for ABO blood groups) or Rh+ (for Rh blood groups) as a reference, odds ratios (ORs) and its 95% confidence intervals (95% CI) of PE risk were estimated from logistic regression analysis.

RESULTS:

Although the A (OR = 0.67, 95% CI = 0.39-1.17, P = 0.165), B (OR = 0.86, 95% CI = 0.48-1.53, P = 0.615) and AB (OR = 1.14, 95% CI = 0.37-3.45, P = 0.812) phenotypes showed lower risks compared with the O blood group, statistical analysis indicated that there was no significant association between ABO phenotypes and risk of PE. The frequency of Rh- phenotype was higher among PE patients compared with the control group. However, the association was not significant (OR = 1.79, 95% CI = 0.69-4.65, P = 0.229). Adjusted ORs for age of participants and parity did not change the above-mentioned associations.

CONCLUSION:

Our present findings indicate that there is no association between ABO and Rh blood groups and risk of PE in Iranian population.

Haemolytic and nonhaemolytic neonatal jaundice have different risk factor profiles

AIM

This study examined maternal and pregnancy risk factors for haemolytic and nonhaemolytic neonatal jaundice in a large population-based cohort study.

METHODS

We conducted a cohort study of 1 019 220 singleton live births from the Swedish medical birth register from 1987 to 2002, using information on neonatal jaundice and maternal and pregnancy characteristics. Diagnoses of gestational hypertensive disorders were obtained by linkage to the national inpatient register. Multivariate logistic regression analysis provided odds ratios for the risk factors of both forms of jaundice.

RESULTS

A total of 6057 (0.6%) births were affected by haemolytic jaundice and 36 869 (3.6%) by nonhaemolytic jaundice. The strongest risk factors for haemolytic jaundice were maternal alloimmunisation, blood group O and neonatal jaundice in older siblings. For nonhaemolytic jaundice, the strongest risk factors were preterm birth, neonatal jaundice in older siblings, maternal origin from East or South-East Asia and maternal obesity. We estimated that 13% of haemolytic jaundice was attributable to alloimmunisation and 39% of nonhaemolytic jaundice was attributable to preterm birth.

CONCLUSION

Haemolytic and nonhaemolytic neonatal jaundice had different risk factor profiles. Interventions to reduce maternal alloimmunisation, preterm birth and maternal obesity may lower the prevalence of neonatal jaundice and the risk of consequent neurological complications.

O Blood Group as Risk Factor for Preeclampsia among Sudanese Women

AIM

To investigate blood groups and the other possible risk factors for preeclampsia among Sudanese women.

MATERIAL AND METHODS

A case - control study was conducted at Saad Abualila Hospital, Khartoum, Sudan during the period of July 2013 through December 2014. The cases were women with preeclampsia and healthy pregnant women were the controls.

RESULTS

Two hundred eighty pregnant women were enrolled (140 in each arm of the study). Around one-quarter of all women (280) were primiparae (74.0, 26.4%), the majority were housewives (201, 71.7%). Seventy-nine (28.2%) were illiterate or had no informal education. Around half of the women (130, 46.4%) had O blood group. Binary logistic regression showed association between preeclampsia and lack of antenatal care (OR = 2.75, 95% CI = 1.172-6.494, P = 0.020) as well as O blood group (OR = 1.78, 95% CI = 1.088-2.934, P=0.022).

CONCLUSION

The current study showed that women with blood group O were at higher risk of preeclampsia.

Relationship between ABO blood group and pregnancy complications: a systematic literature analysis

Given the expression of ABO blood group antigens on the surface of a wide range of human cells and tissues, the putative interplay of the ABO system in human biology outside the area of transfusion and transplantation medicine constitutes an intriguing byway of research. Thanks to evidence accumulated over more than 50 years, the involvement of the ABO system in the pathogenesis of several human diseases, including cardiovascular, infectious and neoplastic disorders, is now acknowledged. However, there is controversial information on the potential association between ABO blood type and adverse pregnancy outcomes, including pre-eclampsia and related disorders (eclampsia, HELLP syndrome and intrauterine growth restriction), venous thromboembolism, post-partum haemorrhage and gestational diabetes. To elucidate the role of ABO antigens in pregnancy-related complications, we performed a systematic review of the literature published in the past 50 years. A meta-analytical approach was also applied to the existing literature on the association between ABO status and pre-eclampsia. The results of this systematic review are presented and critically discussed, along with the possible pathogenic implications.

Are the blood groups of women with preeclampsia a risk factor for the development of hypertension postpartum?

INTRODUCTION

Preeclampsia (PE) is a pregnancy-related disorder characterized by hypertension (HT) and proteinuria noticeable after 20 weeks of gestation. PE is now considered as a cardiovascular disease risk factor and a number of studies have shown that experiencing PE increases the prevalence of various cardiovascular risk factors, such as metabolic syndrome and HT. In this study, we aimed to investigate any possible relationship between the ABO/Rh blood group system and PE in Turkey. In the second part of the study, we examined the relationship between the ABO blood group system and development of HT after PE.

PATIENTS AND METHODS

A total of 250 patients with PE from Kayseri Training and Research Hospital between 2002 and 2012 were included in the study. Patients were classified according to blood groups (A, B, AB, and O) and Rh status (+/-).

RESULTS

There was a significant difference between the patients with PE and the control group in terms of distribution of ABO blood groups and the percentage of group AB was found to be higher in patients with PE compared to the control group (P=0.029). The risk of developing PE was significantly higher in group AB than other blood groups (P=0.006). The risk of developing HT after PE was significantly higher in group O than other blood groups (P=0.004).

DISCUSSION

In this study, we found that the patients with blood group AB have a higher risk for PE. The patients with PE of blood group O are at high risk of developing HT, and Rh factor was identified as another risk at this point and these patients should be closely followed postpartum.

Association of ABO Blood Group Phenotype and Allele Frequency with Chikungunya Fever

Background. The objective of this study was to investigate the association of the ABO blood group phenotype and allele frequency with CHIK fever. Methods. A rural community survey in Southern Thailand was conducted in August and September 2010. A total of 506 villagers were enrolled. Cases were defined as individuals having anti-CHIK IgG by hemagglutination ≥1 : 10. Results. There were 314 cases (62.1%) with CHIK seropositivity. Females were less likely to have positive anti-CHIK IgG with odds ratio (OR) (95% CI) of 0.63 (0.43, 0.93). All samples tested were Rh positive. Distribution of CHIK seropositivity versus seronegativity (P value) in A, B, AB, and O blood groups was 80 versus 46 (0.003), 80 versus 48 (0.005), 24 versus 20 (0.55), and 130 versus 78 (<0.001), respectively. However, chi-square test between ABO and CHIK infection showed no statistical significance (P = 0.76). Comparison of the ABO blood group allele frequency between CHIK seropositivity and seronegativity was not statistically significant. Conclusion. This finding demonstrated no association of the ABO blood group phenotypes and allele frequencies with CHIK infection.

Associations of Rhesus and non-Rhesus maternal red blood cell alloimmunization with stillbirth and preterm birth

BACKGROUND

Although the risks of adverse pregnancy outcomes associated with anti-D antibodies are well-recognized, much less is known concerning alloimmunization with other red blood cell antibodies detected during routine maternal screening. To date, most reports of adverse pregnancy outcomes associated with non-anti-D antibodies have been from small case studies. The aim of this study was to examine the associations of maternal alloimmunization with specific red blood cell antibodies and the risks of preterm birth and stillbirth in the Swedish population.

METHODS

All antibody screening, outcome and covariate data were obtained through linkages of Swedish national health and data registers. Follow-up in these population-based registers was available up to 31 December 2002. The final study sample consisted of 1,022,569 singleton births from 668,952 mothers during 1987-2002.

RESULTS

In total, 1.3% of the 1,022,569 study pregnancies were alloimmunized. In adjusted logistic regression models, compared with having no antibodies, alloimmunization with anti-D, anti-E, anti-C and anti-c was associated with increased risk of both stillbirth and preterm birth. In addition, anti-Kell was associated with increased risk of preterm birth and anti-Lea with increased risk of stillbirth. Compared with firstborn children, risk of preterm birth associated with alloimmunization was greater in subsequent births

CONCLUSIONS

In the largest study to date, alloimmunization with Rhesus, K- and -Lea red blood cell antibodies increased the risk of preterm birth and/or stillbirth. The association of anti-Lea with stillbirth was an unexpected finding. Further study of the consequences of non-anti-D alloimmunization is warranted.