Blood group AB and factor V Leiden as risk factors for pre-eclampsia: a population-based nested case-control study

Rare Blood Groups in ABO, Rh, Kell Systems - Biological and Clinical Significance

Background: The frequency of ABO, Rh and Kell blood group antigens differs among populations of different ethnic ancestry. There are low-frequency antigens (<1%) and high-frequency antigens (>90%). A rare blood group is defined as the absence of a high-frequency antigen in the general population, as well as absence of multiple frequent antigens within a single or multiple blood group systems. Aim: To perform red blood cell typing and to calculate the antigen and phenotype frequencies, in order to identify rare blood group donors within the clinically most important АВО, Rh and Kell systems. Material and Methods: АВО, Rh (D, C, E, c, e) and Kell (K) antigen typing was performed using specific monoclonal sera and microplate technique, while Cellano (k) typing was performed with a monoclonal anti-k, antihuman globulin and column agglutination technique. Weak ABO subgroups were determined using the absorption elution method or molecular genotyping (PCR-SSP). Results: ABO antigen frequency is: A (40.89%), O (34.22%), B (16.97%), AB (7.92%) and weak ABO subgroups (0, 009 %). The established genotypes were AxO1 (0, 0026%) and AxB (0, 001%). Rh antigen frequency is: D (85.79%), C (71.7%), c (76.0%), E (26.0%) and е (97.95%). The most common Rh pheno-type is the DCcee (32.7%) while the rarest phenotype is the DCCEE phenotype (0. 003%). The prevalence of K and k antigen is 7.5% and 99.94%, respectively. The frequency of the rare phenotype K+k- is 0.06%. Conclusion: Large scale phenotyping of blood group antigens enables the identification of blood donors with rare blood groups for patients with rare phenotypes or with antibodies to high-frequency antigens and to frequent antigens within one or more blood group systems.

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.

Oxidative Stress and Preeclampsia-Associated Prothrombotic State

Preeclampsia (PE) is a common obstetric disease characterized by hypertension, proteinuria, and multi-system dysfunction. It endangers both maternal and fetal health. Although hemostasis is critical for preventing bleeding complications during pregnancy, delivery, and post-partum, PE patients often develop a severe prothrombotic state, potentially resulting in life-threatening thrombosis and thromboembolism. The cause of this thrombotic complication is multi-factorial, involving endothelial cells, platelets, adhesive ligands, coagulation, and fibrinolysis. Increasing evidence has shown that hemostatic cells and factors undergo oxidative modifications during the systemic inflammation found in PE patients. However, it is largely unknown how these oxidative modifications of hemostasis contribute to development of the PE-associated prothrombotic state. This knowledge gap has significantly hindered the development of predictive markers, preventive measures, and therapeutic agents to protect women during pregnancy. Here we summarize reports in the literature regarding the effects of oxidative stress and antioxidants on systemic hemostasis, with emphasis on the condition of PE.

The association of the prothrombin G20210A single-nucleotide polymorphism and the risk of preeclampsia: Systematic review and meta-analysis

OBJECTIVE

We conducted this systematic review and meta-analysis to assess the association between the risk of preeclampsia and the prothrombin G20210A single-nucleotide polymorphism.

STUDY DESIGN

We followed the "Preferred Reporting Items for Systematic Reviews and Meta-Analyses" guidelines. Relevant published studies were searched in the data base. The retrieved studies were assessed for quality by using the Modified Newcastle-Ottawa Scale for quality assessment. OpenMeta Analyst software was used for the statistics.

RESULTS

Twenty-eight case-control studies enrolling 3821 cases and 4808 controls were included in this systematic review and meta-analysis. We found a significantly increased preeclampsia risk associated with the G20210A polymorphism in three models: allele contrast (A vs. G), OR 2.183, 95 % CI 1.665-2.862; heterozygote (AG vs. GG), OR 2.233, 95 % CI 1.690-2.95; and the dominant model (AA + AG vs. GG) OR 2.240, 95 % CI 1.700-2.950. However, the association was not observed in the homozygote (AA vs. GG) OR 1.310, 95 % CI = 0.632-2.713 r recessive model (AA vs. AG + GG), OR 1.315, 95 % CI = 0.642-2.695.

CONCLUSIONS

In this meta-analysis, the prothrombin G20210A single-nucleotide polymorphism was associated with an increased risk of preeclampsia.

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.

Evaluation of Factor V Leiden and prothrombin G20210A mutations in Sudanese women with severe preeclampsia

BACKGROUND

Preeclampsia (PE) is a common pregnancy complication and one of the main causes of maternal and fetal morbidity and mortality, worldwide. While the pathogenesis of PE is unclear, it has been suggested that hypercoagulability due to Factor V Leiden (FVL) and prothrombin gene mutation (FII G20210A) play a role in its progression.

PURPOSE

This study aimed to determine if there is an association between FVL and FII G20210A mutations and severe PE.

PATIENTS AND METHODS

This case-control study enrolled 50 women with severe PE and 50 healthy pregnant women as the control, at Khartoum North Teaching Hospital, in Khartoum State, Sudan, from January 2017 to June 2017. The presence of point mutations in FVL and FII G20210A were determined for each of the participants. Deoxyribonucleic acid (DNA) was extracted, and then an allele-specific polymerase chain reaction (PCR) was used to detect the point mutations in FVL and FII G20210A.

RESULTS

The results revealed a significant difference between the subjects in the severe PE group and the control group for the means of parity, gestational age/ week and hemoglobin concentration (P < 0.05). No statistically significant body mass index (BMI) differences were found between the groups (P > 0.05). Women with severe PE were found to have a significant difference in FVL (16%; P value = 0.0058; OR: 20.20; 95%CI: 1.132-360.5) and FII G20210A (14%; P value = 0.0125; OR: 17.41; 95%CI: 0.9659-314.0) in comparison to the women in the control group (0%).

CONCLUSION

Our findings intensely indicate that there is a statistically proven significant association between FVL, FII G20210A mutations and the development of severe preeclampsia in Sudanese pregnant women.

Association of hypertensive disorders of pregnancy risk and factor V Leiden mutation: A meta-analysis

AIM

To date, the conclusions of studies on a possible association between factor V Leiden (FVL, FV G1691A, rs6025) and hypertensive disorders of pregnancy (HDP) are conflicting. Here, we aimed to estimate the relationship between the risk of HDP and FVL.

METHODS

Eligible studies focused on FVL and HDP were searched from the PubMed and the Web of Science databases up to March 31, 2018. We used random effects model for the meta-analysis, and I² statistic to assess the degree of heterogeneity between all included studies. To evaluate the association between FVL and the risk of HDP, we calculated the odds ratio (OR) and 95% confidence intervals (CI) comparing cases and controls of all samples and each subgroup based on different regions.

RESULTS

Fifty citations on FVL and HDP were identified through the literature search, and a meta-analysis on the GA + AA genotype between 6041 cases and 8364 controls was conducted. The holistic analysis found that pregnant women with GA or AA genotype of FVL have a 1.97-fold (95% CI: 1.64-2.35, P < 0.00001) increased risk of HDP compared with GG carriers. While the OR are 2.23 (95% CI: 1.76-2.84, P < 0.00001) and 1.90 (95% CI: 1.12-3.23, P = 0.02) in Europe and the Middle East subgroups, respectively.

CONCLUSION

Factor V Leiden mutation is associated with an increased risk of HDP, and is particularly associated with preeclampsia and eclampsia in European women. However, further high-quality studies are warranted to confirm the possible effectiveness of FVL in HDP patients.

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.

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.

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.

Blood group AB is protective factor for gestational diabetes mellitus: a prospective population-based study in Tianjin, China

BACKGROUND

The ABO blood types are associated with cancers, cardiovascular diseases and type 2 diabetes mellitus but whether they are also associated with gestational diabetes mellitus (GDM) is unknown. We examined the relationship between the ABO blood types and the risk of GDM in a prospective population-based Chinese cohort.

METHODS

From 2010 to 2012, we recruited 14,198 pregnant women within the first 12 weeks of gestation in Tianjin, China. All women had a glucose challenge test (GCT) at 24-28 gestational weeks, followed by a 75-g 2-h oral glucose tolerance test if the results from GCT were ≥7.8 mmol/L. GDM was diagnosed based on the glucose cut-points of the International Association of Diabetes and Pregnancy Study Group criteria. Logistic regression was used to obtain odds ratios (ORs) and 95% confidence intervals (CIs) adjusted for traditional risk factors. Stratified analysis was performed by family history of diabetes (yes versus no). Sensitivity analyses were also performed by using the World Health Organization (WHO) criteria for GDM.

RESULTS

Women with blood groups A, B or O (i.e. non-AB) were associated with increased risk of GDM as compared with those with blood group AB (adjusted OR: 1.44, 95% CI: 1.13-1.83). Sensitivity analyses showed that the result was consistent using WHO criteria. The adjusted OR of blood group non-AB versus AB for GDM was enhanced among women with a family history of diabetes (2.69, 1.21-5.96) and attenuated among those without (1.33, 1.03-1.71).

CONCLUSIONS

Blood group AB was a protective factor against GDM in pregnant Chinese women.

Pre-eclampsia has an adverse impact on maternal and fetal health

Pre-eclampsia (preE) is a multifaceted complication found uniquely in the pregnant patient and one that has puzzled scientists for years. PreE is not a single disorder, but a complex syndrome that is produced by various pathophysiological triggers and mechanisms affecting about 5% of obstetrical patients. PreE is a major cause of premature delivery and maternal and fetal morbidity and mortality. PreE is characterized by de novo development of hypertension and proteinuria after 20 weeks of gestation and affects nearly every organ system, with the most severe consequences being eclampsia, pulmonary edema, intrauterine growth restriction, and thrombocytopenia. PreE alters the intrauterine environment by modulating the pattern of hormonal signals and activating the detrimental cellular signaling that has been transported to the fetus. The fetus has to adapt to this intrauterine environment with detrimental signals. The adaptive changes increase the risk of disease later in life. This review defines the predisposition and causes of preE and the cellular signaling detrimental to maternal health during preE. Moreover, the risk factors for diseases that are transmitted to the offspring have been addressed in this review. The detrimental signaling molecules that have been overexpressed in preE patients raises the possibility that those signals could be therapeutically blocked one day.

Blood groups systems

International Society of Blood Transfusion has recently recognized 33 blood group systems. Apart from ABO and Rhesus system, many other types of antigens have been noticed on the red cell membranes. Blood grouping and cross-matching is one of the few important tests that the anaesthesiologist orders during perioperative period. Hence, a proper understanding of the blood group system, their clinical significance, typing and cross-matching tests, and current perspective are of paramount importance to prevent transfusion-related complications. Nonetheless, the knowledge on blood group system is necessary to approach blood group-linked diseases which are still at the stage of research. This review addresses all these aspects of the blood groups system.

Placental Protein 13 (PP13) - A Placental Immunoregulatory Galectin Protecting Pregnancy

Galectins are glycan-binding proteins that regulate innate and adaptive immune responses, and some confer maternal-fetal immune tolerance in eutherian mammals. A chromosome 19 cluster of galectins has emerged in anthropoid primates, species with deep placentation and long gestation. Three of the five human cluster galectins are solely expressed in the placenta, where they may confer additional immunoregulatory functions to enable deep placentation. One of these is galectin-13, also known as Placental Protein 13 (PP13). It has a "jelly-roll" fold, carbohydrate-recognition domain and sugar-binding preference resembling other mammalian galectins. PP13 is predominantly expressed by the syncytiotrophoblast and released from the placenta into the maternal circulation. Its ability to induce apoptosis of activated T cells in vitro, and to divert and kill T cells as well as macrophages in the maternal decidua in situ, suggests important immune functions. Indeed, mutations in the promoter and an exon of LGALS13 presumably leading to altered or non-functional protein expression are associated with a higher frequency of preeclampsia and other obstetrical syndromes, which involve immune dysregulation. Moreover, decreased placental expression of PP13 and its low concentrations in first trimester maternal sera are associated with elevated risk of preeclampsia. Indeed, PP13 turned to be a good early biomarker to assess maternal risk for the subsequent development of pregnancy complications caused by impaired placentation. Due to the ischemic placental stress in preterm preeclampsia, there is increased trophoblastic shedding of PP13 immunopositive microvesicles starting in the second trimester, which leads to high maternal blood PP13 concentrations. Our meta-analysis suggests that this phenomenon may enable the potential use of PP13 in directing patient management near to or at the time of delivery. Recent findings on the beneficial effects of PP13 on decreasing blood pressure due to vasodilatation in pregnant animals suggest its therapeutic potential in preeclampsia.

Maternal genotype and severe preeclampsia: a HuGE review

Severe preeclampsia is a common cause of maternal and perinatal morbidity worldwide. The disease clusters in families; however, individual genetic studies have produced inconsistent results. We conducted a review to examine relationships between maternal genotype and severe preeclampsia. We searched the MEDLINE and Embase databases for prospective and retrospective cohort and case-control studies reporting associations between genes and severe preeclampsia. Four reviewers independently undertook study selection, quality assessment, and data extraction. We performed random-effects meta-analyses by genotype and predefined functional gene group (thrombophilic, vasoactive, metabolic, immune, and cell signalling). Fifty-seven studies evaluated 50 genotypes in 5,049 cases and 16,989 controls. Meta-analysis showed a higher risk of severe preeclampsia with coagulation factor V gene (proaccelerin, labile factor) (F5) polymorphism rs6025 (odds ratio = 1.90, 95% confidence interval: 1.42, 2.54; 23 studies, I(2) = 29%), coagulation factor II (thrombin) gene (F2) mutation G20210A (rs1799963) (odds ratio = 2.01, 95% confidence interval: 1.14, 3.55, 9 studies, I(2) = 0%), leptin receptor gene (LEPR) polymorphism rs1137100 (odds ratio = 1.75, 95% confidence interval: 1.15, 2.65; 2 studies, I(2) = 0%), and the thrombophilic gene group (odds ratio = 1.87, 95% confidence interval: 1.43, 2.45, I(2) = 27%). There were no associations with other gene groups. There was moderate heterogeneity between studies and potential for bias from poor-quality genotyping and inconsistent definition of phenotype. Further studies with robust methods should investigate genetic factors that might potentially be used to stratify pregnancies according to risk of complications.

Association between thrombophilia gene polymorphisms and preeclampsia: a meta-analysis

OBJECTIVE

To estimate the relationship between the risk of preeclampsia and two thrombophilia gene single-nucleotide polymorphisms (SNPs), the factor V G1691A SNP and the prothrombin G20210A SNP.

DATE SOURCES

A systematic search of the English-language literature up to November 2012 was performed using Medline and EMBASE. Search terms included "preeclampsia," "thrombophilia," "factor V Leiden," "prothrombin gene 20210," and their combinations.

RESULT(S)

Thirty-seven studies with 5048 preeclampsia patients and 6796 controls were included in the meta-analysis. We found that the prothrombin G20210A polymorphism was associated with an increased risk of all preeclampsia (pooled odds ratio (OR) = 1.81, 95% confidence interval (CI) 1.25-2.63) and severe preeclampsia (pooled OR = 3.02, 95%CI 2.06-4.45). Meanwhile, the pooled OR for the association between factor V Leiden and all preeclampsia was 1.60 (95%CI 1.28-2.00) and 2.45 (95%CI 1.63-3.69) for the cases of severe preeclampsia.

CONCLUSION(S)

This meta-analysis supports that the factor V G1691A SNP and the prothrombin G20210A SNP are associated with an increased risk for both preeclampsia overall and severe preeclampsia.

Genetic dissection of the pre-eclampsia susceptibility locus on chromosome 2q22 reveals shared novel risk factors for cardiovascular disease

Pre-eclampsia is an idiopathic pregnancy disorder promoting morbidity and mortality to both mother and child. Delivery of the fetus is the only means to resolve severe symptoms. Women with pre-eclamptic pregnancies demonstrate increased risk for later life cardiovascular disease (CVD) and good evidence suggests these two syndromes share several risk factors and pathophysiological mechanisms. To elucidate the genetic architecture of pre-eclampsia we have dissected our chromosome 2q22 susceptibility locus in an extended Australian and New Zealand familial cohort. Positional candidate genes were prioritized for exon-centric sequencing using bioinformatics, SNPing, transcriptional profiling and QTL-walking. In total, we interrogated 1598 variants from 52 genes. Four independent SNP associations satisfied our gene-centric multiple testing correction criteria: a missense LCT SNP (rs2322659, P = 0.0027), a synonymous LRP1B SNP (rs35821928, P = 0.0001), an UTR-3 RND3 SNP (rs115015150, P = 0.0024) and a missense GCA SNP (rs17783344, P = 0.0020). We replicated the LCT SNP association (P = 0.02) and observed a borderline association for the GCA SNP (P = 0.07) in an independent Australian case-control population. The LRP1B and RND3 SNP associations were not replicated in this same Australian singleton cohort. Moreover, these four SNP associations could not be replicated in two additional case-control populations from Norway and Finland. These four SNPs, however, exhibit pleiotropic effects with several quantitative CVD-related traits. Our results underscore the genetic complexity of pre-eclampsia and present novel empirical evidence of possible shared genetic mechanisms underlying both pre-eclampsia and other CVD-related risk factors.

Maternal ABO blood group and adverse pregnancy outcomes

OBJECTIVE

To determine the relationship between maternal ABO blood group and risk of adverse pregnancy outcomes.

STUDY DESIGN

Data on ABO phenotypes and pregnancy outcomes were collected from medical records of 5320 singleton pregnant women who had ABO blood testing and follow-up care until delivery in our institution. Adverse pregnancy outcomes that were studied in relation to maternal blood group included preeclampsia, gestational diabetes mellitus (GDM), preterm delivery, low birth weight (LBW) and small for gestational age (SGA) infants.

RESULT

Out of 5320 women, 350 (6.6%), 333 (6.3%) and 543 (10.2%) women were diagnosed with preeclampsia, GDM and preterm delivery, respectively. LBW and SGA were, respectively, observed in 394 (7.4%) and 178 (3.3%) infants. By uni- and multivariable analyses, women with A or AB blood types, but not B, were found at increased risk of preeclampsia compared with O type individuals; adjusted relative risks were 1.7 (95% confidence interval (CI), 1.3 to 2.3; P=0.001) for A phenotype and 1.7 (95% CI, 1.1 to 2.6; P=0.01) for AB phenotype. There were no significant relationships between blood types and GDM, preterm delivery, LBW or SGA.

CONCLUSION

Maternal ABO blood group was associated with the risk of preeclampsia, but not with GDM, preterm delivery, LBW or SGA.

Preeclampsia and ABO blood groups: a systematic review and meta-analysis

Preeclampsia (PE) is a multifactorial pregnancy-specific syndrome which represents one of the leading causes of maternal mortality worldwide. Inherited thrombophilia have been investigated as risk factor for the development of PE and it is currently known that ABO blood group may impact haemostatic balance, having the non-O blood groups (A, B or AB) subjects increased risk for thrombus formation, as compared to those of group O. We performed a systematic review of the literature for published studies investigating whether ABO blood groups could influence PE developing. A sensitive search of four databases identified 45 unique titles. The retrieved papers were assessed independently by authors and a rigorous process of selection and data extract was conduct. Methodological quality of the included studies was also evaluated. Two studies met eligibility criteria. As a main finding of our systematic review, an association between the AB blood group and the occurrence of PE was detected based on two original studies. Considering the role of ABO blood groups on the hemostatic process and thrombus formation, special attention should be given to pregnant patients carrying the AB blood group in order to prevent the syndrome and improve prognosis.

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

OBJECTIVE

To examine the association between ABO and RhD blood groups and gestational hypertensive disorders in a large population-based cohort.

DESIGN

Cohort study. Risks of gestational hypertensive disorders, pre-eclampsia, and severe pre-eclampsia, estimated by odds ratios for maternal ABO blood group and RhD status.

SETTING

National health registers of Sweden.

POPULATION

All singleton deliveries in Sweden born to first-time mothers during the period 1987-2002 [total n = 641 926; any gestational hypertensive disorders, n = 39 011 (6.1%); pre-eclampsia cases, n = 29 337 (4.6%); severe pre-eclampsia cases, n = 8477 (1.3%)].

METHODS

Using blood group O as a reference, odds ratios of gestational hypertensive disorders, pre-eclampsia, and severe pre-eclampsia were obtained from logistic regression models adjusted for potential confounding factors.

MAIN OUTCOME MEASURES

Gestational hypertensive disorders, pre-eclampsia, and severe pre-eclampsia.

RESULTS

Compared with blood group O, all non-O blood groups had modest but statistically significantly higher odds of pre-eclampsia. Blood group AB had the highest risk for pre-eclampsia (OR = 1.10, 95% CI 1.04-1.16) and severe pre-eclampsia (OR = 1.18, 95% CI 1.07-1.30). RhD-positive mothers had a small increased risk for pre-eclampsia (OR = 1.07, 95% CI 1.03-1.10).

CONCLUSIONS

In the largest study on this topic to date, women with AB blood group have the highest risks of gestational hypertensive disorders, pre-eclampsia, and severe pre-eclampsia, whereas women with O blood group have the lowest risks of developing these disorders. Although the magnitude of increased risk is small, this finding may help improve our understanding of the etiology of pre-eclampsia.

Genome-wide association scan identifies a risk locus for preeclampsia on 2q14, near the inhibin, beta B gene

Elucidating the genetic architecture of preeclampsia is a major goal in obstetric medicine. We have performed a genome-wide association study (GWAS) for preeclampsia in unrelated Australian individuals of Caucasian ancestry using the Illumina OmniExpress-12 BeadChip to successfully genotype 648,175 SNPs in 538 preeclampsia cases and 540 normal pregnancy controls. Two SNP associations (rs7579169, p = 3.58×10⁻⁷, OR = 1.57; rs12711941, p = 4.26×10⁻⁷, OR = 1.56) satisfied our genome-wide significance threshold (modified Bonferroni p<5.11×10⁻⁷). These SNPs reside in an intergenic region less than 15 kb downstream from the 3′ terminus of the Inhibin, beta B (INHBB) gene on 2q14.2. They are in linkage disequilibrium (LD) with each other (r² = 0.92), but not (r²<0.80) with any other genotyped SNP ±250 kb. DNA re-sequencing in and around the INHBB structural gene identified an additional 25 variants. Of the 21 variants that we successfully genotyped back in the case-control cohort the most significant association observed was for a third intergenic SNP (rs7576192, p = 1.48×10⁻⁷, OR = 1.59) in strong LD with the two significant GWAS SNPs (r²>0.92). We attempted to provide evidence of a putative regulatory role for these SNPs using bioinformatic analyses and found that they all reside within regions of low sequence conservation and/or low complexity, suggesting functional importance is low. We also explored the mRNA expression in decidua of genes ±500 kb of INHBB and found a nominally significant correlation between a transcript encoded by the EPB41L5 gene, ∼250 kb centromeric to INHBB, and preeclampsia (p = 0.03). We were unable to replicate the associations shown by the significant GWAS SNPs in case-control cohorts from Norway and Finland, leading us to conclude that it is more likely that these SNPs are in LD with as yet unidentified causal variant(s).

Association of the rs1424954 polymorphism of the ACVR2A gene with the risk of pre-eclampsia is not replicated in a Finnish study population

BACKGROUND

Pre-eclampsia/eclampsia is a common vascular pregnancy disorder associated with high maternal and infant mortality and morbidity worldwide. The role of Activin A and more recently type 2 Activin A receptor (ACVR2A) in the pathogenesis of pre-eclampsia has been the subject of genetic and biochemical research with controversial results.

FINDINGS

We genotyped a candidate pre-eclampsia-associated single nucleotide polymorphism rs1424954 in ACVR2A in three independent study populations of Finnish pre-eclamptic (total N = 485) and non-pre-eclamptic (total N = 449) women using pre-designed TaqMan allele discrimination assay and polymerase chain reaction. The possible association of the alleles and genotypes of interest with pre-eclampsia was evaluated using the chi-square test and logistic regression analysis. We found no association of rs1424954 to pre-eclampsia in Finnish patients.

CONCLUSIONS

rs1424954 was not associated to pre-eclampsia in the Finnish study population. We hypothesise that while the gene associates to pre-eclampsia worldwide, the causative polymorphism in ACVR2A may be unique in genetically differing populations. Further research is needed to characterise the haplotype structure of ACVR2A in order for the causative genetic variant to be identified.

An obesity-related FTO variant and the risk of preeclampsia in a Finnish study population

Previous studies have demonstrated a common variant of the obesity and fat mass-related FTO gene, rs9939609, to be associated with obesity, type 2 diabetes, and elevated blood pressure. We investigated whether the FTO SNP rs9939609 is associated with the risk of preeclampsia (PE) in a Finnish study population. 485 women with prior PE and 449 women who had given birth after a normotensive pregnancy were genotyped (TaqMan) for the SNP rs9939609. The prevalences of genotypes AA, AT, and TT were 15%, 53%, and 32%, respectively, among the PE cases, and 16%, 47%, and 37%, respectively, among the controls (P = 0.199). We found no evidence of an association between the FTO SNP rs9939609 and PE. However, our cases were dominated by severe, early-onset PE. Thus, we are unable to exclude an association with the milder, later-onset form of the disease in which the role of maternal metabolic predisposition could be more significant.

ADAMTS13, FVIII, von Willebrand factor, ABO blood group assessment in preeclampsia

INTRODUCTION

Preeclampsia (PE) is a multifactorial disease characterized by high blood pressure and proteinuria after the 20th week of pregnancy. PE is associated with fibrin deposition in placental microcirculation and intrauterine fetal growth retardation. We evaluated FVIII activity, VWF and ADAMTS13 plasma levels, according to O and "non O" blood groups, in women with severe PE (sPE).

METHODS

This case-control study included 140 women; 55 pregnant with sPE, 35 normotensive pregnant and 50 non-pregnant women. VWF and ADAMTS13 antigen levels were assessed by ELISA (American Diagnostica). FVIII activity was measured by automated coagulometric method (Dade Behring) and ABO blood groups phenotyping was performed by indirect technique.

RESULTS

FVIII activity and VWF levels were significantly higher comparing either sPE to normotensive pregnant (P=0.01; P=0.05) and to non-pregnant women (P=0.00 in both cases) or normotensive pregnant and non-pregnant women (P=0.00 in both cases). A significant decrease in ADAMTS13 levels was observed comparing either sPE to normotensive pregnant (P=0.02) and non-pregnant women (P=0.00) or normotensive pregnant and non-pregnant women (P=0.00). FVIII activity and VWF levels were associated to O and "non O" blood groups only in non-pregnant women.

CONCLUSIONS

The increase of FVIII activity and VWF levels and the decrease of ADAMTS13 in sPE are not associated to O and "non O" blood groups. These alterations in hemostatic markers in sPE largely surpass those physiologically determined by ABO blood groups influence and may have masked the effect of O and "non O" groups in this disease. A concomitant analysis of VWF levels and ADAMTS13 activity and antigenic levels will be important to clarify the imbalance between these parameters found in sPE in the present study.

PP13, maternal ABO blood groups and the risk assessment of pregnancy complications

BACKGROUND

Placental Protein 13 (PP13), an early biomarker of preeclampsia, is a placenta-specific galectin that binds beta-galactosides, building-blocks of ABO blood-group antigens, possibly affecting its bioavailability in blood.

METHODS AND FINDINGS

We studied PP13-binding to erythrocytes, maternal blood-group effect on serum PP13 and its performance as a predictor of preeclampsia and intrauterine growth restriction (IUGR). Datasets of maternal serum PP13 in Caucasian (n = 1078) and Hispanic (n = 242) women were analyzed according to blood groups. In vivo, in vitro and in silico PP13-binding to ABO blood-group antigens and erythrocytes were studied by PP13-immunostainings of placental tissue-microarrays, flow-cytometry of erythrocyte-bound PP13, and model-building of PP13--blood-group H antigen complex, respectively. Women with blood group AB had the lowest serum PP13 in the first trimester, while those with blood group B had the highest PP13 throughout pregnancy. In accordance, PP13-binding was the strongest to blood-group AB erythrocytes and weakest to blood-group B erythrocytes. PP13-staining of maternal and fetal erythrocytes was revealed, and a plausible molecular model of PP13 complexed with blood-group H antigen was built. Adjustment of PP13 MoMs to maternal ABO blood group improved the prediction accuracy of first trimester maternal serum PP13 MoMs for preeclampsia and IUGR.

CONCLUSIONS

ABO blood group can alter PP13-bioavailability in blood, and it may also be a key determinant for other lectins' bioavailability in the circulation. The adjustment of PP13 MoMs to ABO blood group improves the predictive accuracy of this test.

ABO blood groups and thrombosis: a causal association, but is there value in screening?

ABO(H) antigens are expressed on red cells and on von Willebrand factor. An association between groups other than O and thrombosis exists: an effect that is predominantly mediated by von Willebrand factor. Overall, the risk of venous thrombosis associated with non-O has been estimated at 1.75-fold, with a higher risk (∼2.4-fold) in those with the least O(H) antigen (a combined group of A1A1/A1B/BB). Preliminary evidence also suggests that blood group may influence the venous thromboembolism risk associated with factor V Leiden. Overall, ABO(H) has a more modest effect on arterial disease, with a consistent effect observed in peripheral vascular disease and no influence evident with angina. A modest effect on myocardial infarction and stroke has been reported in some but not all studies. The potential mechanisms whereby blood group influences thrombosis, the limitations of current evidence and the current and future role of blood groups in identifying those at risk of arterial and venous disease is discussed.

Factor V Leiden as a risk factor for preterm birth--a population-based nested case-control study

BACKGROUND

Preterm birth is a major cause of neonatal morbidity and mortality, occurring in 5-13% of deliveries in developed countries. Genetic thrombophilia can theoretically contribute to the induction of preterm delivery, but the role of thrombophilia as risk factor is unclear.

OBJECTIVES

To assess factor V Leiden, FII G20210A and other selected inherited and acquired variables as risk factors for preterm birth.

PATIENTS/METHODS

We performed a population-based nested case-control study of 100,000 consecutive pregnancies in Finland. Cases and controls were identified by combining national registers. Clinical data were obtained from medical records and standardized questionnaires. We studied 324 cases with preterm delivery at or after 22 and before 37 completed weeks of gestation, and 752 controls.

RESULTS

FV Leiden was associated with a 2.4-fold risk (95% confidence interval [CI] 1.3-4.6) of preterm birth in all pregnancies, and a 2.6-fold risk (95% CI 1.4-5.1) in singleton pregnancies. FV Leiden was especially associated with late preterm birth at or after 32 weeks of pregnancy, with an odds ratio (OR) of 2.9 (95% CI 1.5-5.6) in all pregnancies and an OR of 3.1 (95% CI 1.6-6.2) in singleton pregnancies. FII G20210A was not associated with preterm birth. Twin pregnancy (OR 12.0, 95% CI 6.0-24.1) and a history of venous thrombosis (OR 3.8, 95% CI 1.4-9.8) were associated with increased risk. High educational level and modest overweight (body mass index 25-29.9 kg m(-2) ) had protective effects.

CONCLUSIONS

Maternal carriage of FV Leiden was associated with increased risk of late but not early preterm birth. FII G20120A was not associated with preterm birth.

Heritability of apnea of prematurity: a retrospective twin study

BACKGROUND

Apnea of prematurity (AOP) is a disturbance in respiratory rhythm defined by idiopathic pauses in breathing that reduce blood oxygen levels and/or heart rate. It is a major clinical problem among preterm infants.

OBJECTIVES

The primary goal of this study was to estimate the genetic susceptibility to AOP in a cohort of preterm twins. A secondary aim was to identify risk factors associated with AOP in this cohort.

METHODS

A single-center, retrospective study (2000-2008) was performed by using data from 317 premature twin pairs (<36 weeks' gestational age). Heritability estimates were determined by comparing intrapair AOP concordance between 56 monozygotic and 161 dizygotic twin pairs by using structural equation modeling. Risk factors of AOP among a cohort of 543 premature twins were assessed by using mixed-effects logistic regression.

RESULTS

The heritability of AOP was 87% (95% confidence interval [CI]: 0.64-0.97) among same-gender twins. A gender-dependent model revealed that genetic factors accounted for 99% of the variance in male twins (95% CI: 0.89-1.00) and 78% of the variance in female twins (95% CI: 0.49-0.94). Significant risk factors for AOP were low gestational age (P<.001), cesarean delivery (P=.017), and conception through assisted reproductive technologies (P=.008).

CONCLUSIONS

These findings suggest that AOP has an important genetic basis underlying this developmental-related disorder of respiratory control. Future genomic studies may provide information on pathophysiological mechanisms that underlie AOP.

Risk factors and prediction of preeclampsia

Inadequate trophoblast invasion of the spiral arteries in early pregnancy, an increased inflammatory response and changes in the immune answer to paternal antigens are considered aetiological factors in preeclampsia. Searching for factors related to these angiogenic, anti-angiogenic, immunologic and inflammatory mechanisms may provide methods to determine which patient will develop preeclampsia predating the onset of the clinical manifestations of the disease. Screening for preeclampsia in the first trimester has had Limited success. Currently, maternal characteristics, clinical history, maternal serum biochemistry and uterine artery Doppler sonography before 14 weeks are being investigated. Preeclampsia in a previous pregnancy is still the strongest predictor. In the second trimester, uterine artery Doppler has a detection rate around 60% but also a high false positive rate of 25%. First trimester uterine artery Doppler studies have high sensitivity but poor specificity with a high false positive rate. Combination of first trimester uterine artery Doppler with patient characteristics and maternal serum biochemistry, specifically placental protein 13 holds promise but further evaluation is needed. Maternal serum markers including inhibin A, activin A, soluble FMS-Like tyrosine kinase 1, endoglin, pregnancy associated plasma protein A and others, when used alone have proved poor predictors of preeclampsia. Most studies have been performed by a limited group of researchers in a population with a high risk and no validation studies of any method in other populations are available. Results are difficult to compare due to differences in methodology, and differences in the end point studied.There are still no good methods of preventing preeclampsia once a high risk has been determined.