Preeclampsia and genetic risk factors for thrombosis: a case-control study

Protein S antibody as an adjunct therapy for hemophilia B

ABSTRACT

Hemophilia B (HB) is caused by an inherited deficiency of plasma coagulation factor IX (FIX). Approximately 60% of pediatric patients with HB possess a severe form of FIX deficiency (<1% FIX activity). Treatment typically requires replacement therapy through the administration of FIX. However, exogenous FIX has a limited functional half-life, and the natural anticoagulant protein S (PS) inhibits activated FIX (FIXa). PS ultimately limits thrombin formation, which limits plasma coagulation. This regulation of FIXa activity by PS led us to test whether inhibiting PS would extend the functional half-life of FIX and thereby prolong FIX-based HB therapy. We assayed clotting times and thrombin generation to measure the efficacy of a PS antibody for increasing FIX activity in commercially obtained plasma and plasma from pediatric patients with HB. We included 11 pediatric patients who lacked additional comorbidities and coagulopathies. In vivo, we assessed thrombus formation in HB mice in the presence of the FIXa ± PS antibody. We found an accelerated rate of clotting in the presence of PS antibody. Similarly, the peak thrombin formed was significantly greater in the presence of the PS antibody, even in plasma from patients with severe HB. Furthermore, HB mice injected with PS antibody and FIX had a 4.5-fold higher accumulation of fibrin at the thrombus induction site compared with mice injected with FIX alone. Our findings imply that a PS antibody would be a valuable adjunct to increase the effectiveness of FIX replacement therapy in pediatric patients who have mild, moderate, and severe HB.

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.

Cardiovascular risk after hypertensive disorders of pregnancy in women with and without inheritable Thrombophilia

Aim of this study was to compare cardiovascular risk in women with and without inheritable thrombophilia after hypertensive disorders of pregnancy (HDP). Blood pressure, anthropometrics and blood samples were measured 9-13 years after early-onset (<34 weeks) HDP. Amongst the 114 women included, no differences in hypertension (31.1% vs. 33.7%, OR 0.90 95% CI (0.29-2.79)), body mass index > 25 kg/m² (43.8% vs. 53.1%, OR 0.69 95% CI (0.24-2.00)) or metabolic syndrome (18.8% vs. 13.3%, OR 1.51 95% CI (0.38-6.02)) were found. These data show similar cardiovascular risk profile in women with and without inheritable thrombophilia.

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.

Evolution of Factor V Leiden

Factor V Leiden is a procoagulant mutation associated with venous and arterial thrombosis and pregnancy complications. Its high prevalence of 5% in Caucasians suggests that there are evolutionary benefits as well. Carriers are indeed reported to have various advantageous phenotypes related to haemostasis, inflammation and fertility: less acute blood loss; less menstrual blood loss; decreased risk of intracranial haemorrhage; milder phenotypes of haemophilia; higher survival in and lower susceptibility to severe sepsis; higher survival in acute respiratory distress syndrome; less severe diabetic nephropathy and higher fecundity in both men and women. Not all these associations come from high quality adequately powered studies and many have not been confirmed by further research. The evolutionary influence of the alleged associations varies and is difficult to establish, partly due to a shift over time in risk factors of the diseases concerned. For most of the phenotypes possible mechanistic explanations can be provided. The procoagulant phenotype and perhaps also certain pregnancy complications follow from activated protein C (APC) resistance. Elevated APC levels possibly mediate anti-inflammatory effects. Higher sperm counts and more successful embryo implantation seem to play a role in the increased fecundity.

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 aspects of preeclampsia and the HELLP syndrome

Both preeclampsia and the HELLP syndrome have their origin in the placenta. The aim of this study is to review genetic factors involved in development of preeclampsia and the HELLP syndrome using literature search in PubMed. A familial cohort links chromosomes 2q, 5q, and 13q to preeclampsia. The chromosome 12q is coupled with the HELLP syndrome. The STOX1 gene, the ERAP1 and 2 genes, the syncytin envelope gene, and the −670 Fas receptor polymorphisms are involved in the development of preeclampsia. The ACVR2A gene on chromosome 2q22 is also implicated. The toll-like receptor-4 (TLR-4) and factor V Leiden mutation participate both in development of preeclampsia and the HELLP syndrome. Carriers of the TT and the CC genotype of the MTHFR C677T polymorphism seem to have an increased risk of the HELLP syndrome. The placental levels of VEGF mRNA are reduced both in women with preeclampsia and in women with the HELLP syndrome. The BclI polymorphism is engaged in development of the HELLP syndrome but not in development of severe preeclampsia. The ACE I/D polymorphism affects uteroplacental and umbilical artery blood flows in women with preeclampsia. In women with preeclampsia and the HELLP syndrome several genes in the placenta are deregulated. Preeclampsia and the HELLP syndrome are multiplex genetic diseases.

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.

Factor V Leiden mutation and its impact on pregnancy complications

OBJECTIVE

The aim of this prospective study was to find the association between the factor V Leiden mutation and adverse pregnancy outcomes.

METHODS

This study is an analysis of a prospective observational study of the frequency of placenta-mediated complications of factor V Leiden mutation carriers. We compared pregnancy outcomes of 11 women with a heterozygous form of the factor V Leiden mutation with 41 women of a control group.

RESULTS

All pregnancies ended with delivery of a living infant. None of the 52 pregnancies were complicated by venous thromboembolism. There were a few significant differences regarding placenta-mediated complications. The gestational age at delivery showed small significant differences. There was a significant difference in the birth weight deviation in percentage between FVL carriers and controls. The incidence of blood loss exceeding 1000 ml was higher in the control group.

CONCLUSIONS

Carriership of the factor V Leiden mutation did not affect the incidence of preeclampsia. Adverse pregnancy outcomes such as placental abruption were rare. Eclampsia, intrauterine fetal death and venous thromboembolism did not occur. Our results provide evidence that the maternal heterozygous FVL mutation did not increase the risk of an adverse pregnancy outcome.

Gene expression in chorionic villous samples at 11 weeks of gestation in women who develop pre-eclampsia later in pregnancy: implications for screening

OBJECTIVES

To determine the gene expression profile in chorionic villous samples (CVSs) of women destined to develop pre-eclampsia (PE).

METHOD

Case-control study encompassing five women destined to develop PE [cases matched for gestational age with 30 controls]. We quantified mRNA expression on tissue samples from CVS of normal and PE patients. We then assessed mRNA expressions of cathepsin (CTSD), angiopoietin 2 (ANGPT2), interleukin 8, chemokine (C-X-C motif) ligand 10, neurokinin B (NKB), matrix metallopeptidase 9, major histocompatibility complex, class I, C (HLA-C)and human leukocyte antigen-G (HLA-G). Data were analyzed by nonparametric rank analysis.

RESULTS

For all the mRNA species considered in this study, except CTSD and ANGPT2, all the mean observed ranks in the PE group were significantly altered compared with the rank expectation among controls. mRNA for NKB and HLA-C were the markers with the highest degree of aberration in PE, compared with those in controls.

CONCLUSION

Our study has directly showed that gene expressions relating to trophoblastic cell invasion or utero-placental hemodynamic adaptation are altered in the first trimester trophoblasts that go on to develop PE later. These results posit the use of residual CVS as a possible screening method for PE.

Performance of messenger RNAs circulating in maternal blood in the prediction of preeclampsia at 10-14 weeks

OBJECTIVE

The purpose of this study was to determine whether the combined distribution of a panel of cellular messenger RNA markers can detect preeclampsia long before onset.

STUDY DESIGN

We compared blood at 10-14 weeks from 11 women who ultimately experienced preeclampsia with 88 matched control subjects. After multiples of the median conversion of all the markers, logistic regression was used to calculate the risk of the development of preeclampsia.

RESULTS

Higher multiples of the median values than expected were found for endoglin, fms-related tyrosine kinase 1, and transforming growth factor-β1. Lower multiples of the median values were found for placental growth factor and placental protein 13. Endoglin fms-related tyrosine kinase 1 and transforming growth factor-β1 had the best discriminant power. Messenger RNA species provided independent contributions to the prediction of preeclampsia. In fact, 11 women with preeclampsia scored a median risk of 50% of experiencing preeclampsia. Control subjects scored a median risk of preeclampsia of 0.18%. The detection rate at a 5% false positive rate was 72.3%.

CONCLUSION

The messenger RNA dosage in maternal blood would be a useful method for the calculation of the risk of the development of preeclampsia.

Factor V Leiden mutation and pregnancy-related complications

OBJECTIVE

The objective of the study was to determine the prevalence of the factor V Leiden (FVL) mutation and its association with obstetric complications, blood loss during delivery, and venous thromboembolism (VTE).

STUDY DESIGN

This was a prospective, observational, case-cohort study of 491 FVL carriers and 1055 controls derived from 6003 screened women. Data were analyzed with a Student t test and cross-tabulation.

RESULTS

FVL carriership prevalence was 8.3%. Gestational age at delivery, birthweight deviation, gestational hypertension, and preeclampsia incidences did not differ between groups. The incidences of placental abruption, neonatal asphyxia, eclampsia, intrauterine fetal death, intrapartum death, and unexplained late miscarriage were low. The incidence of major blood loss at delivery was lower in carriers. There were 3 VTEs among carriers and none among controls.

CONCLUSION

FVL carriership did not influence pregnancy-induced hypertension, birthweight, or prematurity but raised the risk of venous thromboembolism and lowered the risk of major blood loss.

[Late prognosis after preeclampsia]

Preeclampsia, eclampsia and HELLP syndrome are severe complications of pregnancy associated with a high morbidity and mortality for both mother and foetus. The issue of prognosis with regards to risk of relapse is therefore of upmost importance for both the patients and doctors managing their subsequent pregnancies. The overall risk of relapse is estimated to be less than 10%. The risk is especially increased in case of early onset, before the 28(th) week of amenorrhea. In such patients, an underlying renal disease, essential hypertension or secondary hypertension might be identified. A renal consultation must ensure the complete resolution of the hypertension and proteinuria, otherwise investigations need to be carried out looking for an underlying renal or vascular disease affecting the renal parenchyma or outflow. Screening for a hereditary thrombophilia is performed in the immediate post-partum period following and early onset PE, especially if associated with an IUGR, fetal death, or in an early and severe relapse. A renal biopsy is only rarely considered: it is either performed within the first post-partum days whenever a systemic disease flare-up is suspected (i.e. SLE), or late if the proteinuria failed to settle beyond 6 months post-part. Severe PE is a marker of a vascular disease of short duration, but must be considered a risk factor for later atherosclerosis with cardiovascular complications, justifying long term cardiovascular, renal and metabolic follow-up.

Gene expression in chorionic villous samples at 11 weeks of gestation in women who develop preeclampsia later in pregnancy: implications for screening

OBJECTIVES

To determine the gene expression profile in chorionic villous samples (CVS) of women destined to develop preeclampsia.

METHOD

cDNA microarray technology was employed. Ten singleton fetuses of women who subsequently developed preeclampsia where compared with a pool of 50 controls. The mRNA expression of some of the genes previously found to be up- or down-regulated were validated by RT-PCR in peripheral blood from 23 pregnant women at term affected with preeclampsia and 23 controls.

RESULTS

Altered expression was found among several genes including those involved in invasion of human trophoblasts (Titin), in inflammatory stress (Lactotransferrin), endothelial aberration (Claudin 6), angiogenesis (Vasohibin 1), blood pressure control (Adducin 1). Also the peripheral blood from preeclampsia patients showed significant differences for all the genes studied.

CONCLUSION

CVS show an aberrant gene profile prior to preeclampsia onset that may be predictive of the disease.

Genetic thrombophilia variants and risk for preeclampsia among American Indians

OBJECTIVE

To determine the prevalence of thrombophilic genetic variants in an American Indian population and determine if they are associated with preeclampsia.

METHODS

A total of 87 cases, 165 controls and an additional 75 population-based controls were genotyped for two thrombophilic polymorphisms.

RESULTS

The allelic prevalence of the factor V Leiden and 20210 G/A prothrombin variants in this population was 2.1% and 0.5% respectively. No statistically significant associations between these genetic variants and preeclampsia were found.

CONCLUSION

The prevalence of thrombophilic variants is of possible public health significance for other morbidity; but perhaps not in relation to preeclampsia.

Gene expression in chorionic villous samples at 11 weeks' gestation from women destined to develop preeclampsia

OBJECTIVE

To evaluate the direct alterations in mRNA expression among chorionic villous samples from 11 weeks' pregnant women who would develop preeclampsia (PE) later in the pregnancy.

METHOD

Case-control study encompassing five women destined to develop PE [cases matched 1:5 for gestational age (GA) with 25 controls]. We quantified mRNA expression on tissue samples from chorionic villous sampling (CVS) of normal and PE patients. We then assessed mRNA expressions of vascular endothelial growth factor (VEGFA), VEGFA receptor 1 (Flt-1), endoglin (Eng), placental growth factor (PlGF), transforming growth factor-beta1 (TGF-beta1), heme oxygenase-1 (HO-1) and superoxide dismutase (SOD). Data were analyzed by nonparametric rank analysis.

RESULTS

For all the mRNA species considered in this study, all the mean observed ranks in the PE group were significantly altered compared to the rank expectation among controls. mRNA for Eng and TGF-beta1 were the markers with the highest degree of aberration in PE, in respect to controls. The results are consistent with those already reported for the corresponding circulating proteins. mRNA for HO-1 and SOD were instead associated with the lowest aberration.

CONCLUSION

It is assumed that the pathogenesis of PE is associated with pathophysiological alterations to trophoblasts in early gestation. Our study has directly proved that gene expressions relating to angiogenesis or oxidative stress are altered in the first trimester trophoblasts that go on to develop PE later. These results would put the basis for a possible screening method for PE by using residual CVS.

Mannose-binding lectin polymorphisms are not associated with rheumatoid arthritis--confirmation in two large cohorts

OBJECTIVES

In RA, conflicting results have been described on the association between genotypes of the complement factor mannose-binding lectin (MBL) and disease susceptibility and severity. This might be due to underpowerment of previous research work and the fact that no confirmation cohorts were used. Therefore a different approach is warranted.

METHODS

MBL2 gene polymorphisms were determined in two RA cohorts (378 and 261 cases) and 648 controls. Considering MBL polymorphisms, cases and controls were categorized in groups of high, intermediate and low MBL production. The total sample size allows detection of a potential association between RA susceptibility and MBL groups with an odds ratio of 1.37 (alpha < 0.05; 1-beta > 0.8). Disease severity as defined by the need for anti-TNF therapy was also analysed for possible associations with MBL groups.

RESULTS

There was no difference in the frequencies between MBL genotypes of RA cases and controls that are associated with high (cases 54.4%, controls 57.0%), intermediate (cases 28.9%, controls 27.5%) or low (cases 16.7%, controls 15.5%) MBL production. Furthermore, there was no association between MBL groups and disease severity.

CONCLUSIONS

MBL genotype groups are not associated with RA disease susceptibility or severity in this large study including a confirmation cohort. Compared with previous smaller studies these results add to more definite conclusions.

Genes and the preeclampsia syndrome

Preeclampsia is specific to pregnancy and is still a leading cause of maternal and perinatal mortality and morbidity, affecting about 3% of women, but the underlying pathogenetic mechanisms still remain unclear. Immune maladaptation, placental ischemia and increased oxidative stress represent the main components discussed to be of etiologic importance, and they all may have genetic implications. Since the familial nature of preeclampsia is known for many years, extensive research on the genetic contribution to the pathogenesis of this severe pregnancy disorder has been performed. In this review, we will overview the linkage and candidate gene studies carried out so far as well as summarize important historical notes on the genetic hypotheses generated in preeclampsia research. Moreover, the influence of maternal and fetal genes and their interaction as well as the role of genomic imprinting in preeclampsia will be discussed.

Maternal TLR4 and NOD2 gene variants, pro-inflammatory phenotype and susceptibility to early-onset preeclampsia and HELLP syndrome

BACKGROUND

Altered maternal inflammatory responses play a role in the development of preeclampsia and the hemolysis, elevated liver enzymes and low platelets (HELLP) syndrome. We examined whether allelic variants of the innate immune receptors Toll-like receptor 4 (TLR4) and nucleotide-binding oligomerization domain 2 (NOD2), that impair the inflammatory response to endotoxin, are related to preeclampsia and HELLP syndrome.

METHODS AND FINDINGS

We determined five common mutations in TLR4 (D299G and T399I) and NOD2 (R702W, G908R and L1007fs) in 340 primiparous women with a history of early-onset preeclampsia, of whom 177 women developed HELLP syndrome and in 113 women with a history of only uneventful pregnancies as controls. In addition, we assessed plasma levels of pro-inflammatory biomarkers C-reactive protein, interleukin-6, soluble intercellular adhesion molecule-1, fibrinogen and von Willebrand factor in a subset of 214 women included at least six months after delivery. After adjustment for maternal age and chronic hypertension, attenuating allelic variants of TLR4 were more common in women with a history of early-onset preeclampsia than in controls (OR 2.9 [95% CI 1.2-6.7]). Highest frequencies for TLR4 variants were observed in women who developed HELLP syndrome (adjusted OR 4.1 [95% CI 1.7-9.8]). In addition, high levels of interleukin-6 and fibrinogen were associated with a history of early-onset preeclampsia. Combined positivity for any of the TLR4 and NOD2 allelic variants and high levels of interleukin-6 was 6.9-fold more common in women with a history of early-onset preeclampsia (95% CI 2.1-23.2) compared to controls.

CONCLUSIONS

We observed an association of common TLR4 and NOD2 gene variants, and pro-inflammatory phenotype with a history of early-onset preeclampsia and HELLP syndrome. These findings suggest involvement of the maternal innate immune system in severe hypertensive disorders of pregnancy.

Thrombophilia and adverse pregnancy outcome

This article focuses on the clinical evaluation and management of women who have thrombophilia-related placental vascular complications, including fetal loss, pre-eclampsia, intrauterine fetal growth restriction, and placental abruption. All are major causes of maternal and fetal adverse outcomes.

Antithrombotic therapy and pregnancy: consensus report and recommendations for prevention and treatment of venous thromboembolism and adverse pregnancy outcomes

Venous thromboembolism and adverse pregnancy outcomes are potential complications of pregnancy. Numerous studies have evaluated both the risk factors for and the prevention and management of these outcomes in pregnant patients. This consensus group was convened to provide concise recommendations, based on the currently available literature, regarding the use of antithrombotic therapy in pregnant patients at risk for venous thromboembolic events and adverse pregnancy outcomes.

Inherited thrombophilias and pre-eclampsia in Brazilian women

OBJECTIVE

The aim of the present study was to compare the distribution of G1691A, G20210A and C677T mutations in pre-eclamptic Brazilian women and in matched control women with an uncomplicated normal pregnancy.

STUDY DESIGN

these mutations were investigated by PCR-RFLP in 83 normal pregnancies (control group) and in 30 pre-eclamptic pregnant women (severe form).

RESULTS

G1691A mutation was detected neither in the control group nor in pre-eclamsia women. G20210A mutation was detected in heterozygosis in 3 (3.61%) control subjects, but not in pre-eclampsia group. C677T mutation was detected in homozygosis in 6 (7.23%) control subjects and 2 (6.67%) pre-eclamptic women and in heterozygosis in 31 (37.3%) control subjects and 12 (40%) pre-eclamptic women. Differences in the mutation frequencies detected in the two groups were not statistically significant.

CONCLUSION

No correlation was observed between pre-eclampsia and presence of G1691A, G20210A and C677T mutations in Brazilian women.

Prospective evaluation of the risk of pre-eclampsia using logistic regression analysis

OBJECTIVES

To calculate the risk of developing pre-eclampsia (PET) in a consecutive series of low-risk women at 18-24 weeks' gestation, using recently published logistic regression models.

METHODS

This was a prospective study, with complete follow-up, in a consecutive series of unselected low-risk singleton pregnancies. Uterine artery pulsatility index as well as a combination of maternal factors were recorded at 18-24 weeks' gestation. The distribution of the estimated risks for the 16 PET patients was compared with that obtained for 136 women who had a normal pregnancy, as assessed by routine testing. A receiver-operating characteristics (ROC) curve was plotted to evaluate the detection rate at fixed false-positive rates (FPRs) of 5%, 10% and 20% and the corresponding odds cut-offs.

RESULTS

Just 1/16 (6.2%) women with PET developed the disease before the 34(th) week of gestation. Using the 'All PET' logistic regression model, for 16 PET cases the overall median odds was 1 : 1454, higher compared with that of 1 : 41635 estimated for controls. Using the 'PET >or= 34 weeks' model, the median odds of the 15 women who developed PET late was 1 : 3405, compared with 1 : 40785 for controls. In the case of PET before 34 weeks, the risk was 1 : 426373 vs. 1 : 4159823126 estimated for controls ('PET < 34 weeks' model). Detection rates for the All PET model were 18%, 50% and 62% at a FPR of 5%, 10% and 20%, respectively. For the PET >or= 34 weeks model these detection rates were 6%, 46% and 60%, respectively.

CONCLUSION

Even though the individual odds estimation is too low to represent the real risk of PET, the recently published logistic regression models detected more than 60% of PET at a FPR of 20% for both All PET and PET >or= 34 weeks models. Using these models in clinical practice does not seem to give any significant improvement over Doppler alone in the prediction of PET, but the use of a PET-specific odds instead of an actual Doppler value alone seems to be useful for clinical management.

Performance of a panel of maternal serum markers in predicting preeclampsia at 11–15 weeks' gestation

OBJECTIVE

We evaluated whether a discriminant model of prediction based on quantitative distribution of a panel of biomolecules in maternal serum can discriminate normal pregnancies from those who will develop preeclampsia (PE) prior to onset of clinical symptoms at 11-15 weeks' gestation.

METHODS

Case control study encompassing 56 women destined to develop PE cases matched 1:3 for gestational age with 168 controls. After multiple of median (MoM) conversion of all available markers, comprising total Activin A (t-activin A), P-selectin, and vascular endothelial growth factor receptor (VEGFR) the combined likelihood ratios generated for each marker were used to calculate, for each patient enrolled in the study, the odds of being affected given a positive results (OAPR) of developing PE. For all the analyses performed, the type II error was < 20% with a type I error fixed at 5%.

RESULTS

Data were expressed in MoM of controls. P-selectin was identified as the marker with the best discriminant ability between controls and PE, followed by (t-activin A). No significant differences in VEGFR were observed between cases and controls. By using a 3% prevalence of PE (or, about 1:33) we found that the median OAPR of developing PE for the 56 cases was 1:9 or 10% (1:1-1:417). The median OAPR of PE for controls was 1:40 or 2.5% (range, 1:6-1:4205). Detection rate of the statistical model, with a 5% false-positive rate was 59%.

CONCLUSION

This analysis revealed that maternal serum markers assessed at the first and second trimester of pregnancy in asymptomatic patients can improve the early detection of cases at higher risk of developing PE.

Thrombophilia and Adverse Maternal-Perinatal Outcome

A recent review of the literature on thrombophilia and adverse pregnancy outcome (APO) reveals contradictory findings. We have limited our review of literature mostly to the most recent decade. On the basis of our review, screening for thrombophilias with a history of APO (preeclampsia, abruptio placenta, intrauterine growth restriction, and fetal loss) is not clear. There are retrospective and prospective studies that recommend testing for genetic and acquired markers of thrombophilia for those with the enumerated APO. The rationale for such recommendation is to use heparin prophylaxis in subsequent pregnancies. However, this recommendation is not based on randomized trials. Hence, a randomized double-blinded controlled trial is urgently needed to evaluate the benefit of heparin during pregnancy in women with a history of APO in association with thrombophilia.

Matrix metalloproteinase-9 gene -1562C/T polymorphism mitigates preeclampsia

Although the aetiology of preeclampsia is unknown, there is substantial evidence that it finds its roots in abnormal placentation. Prerequisites for successful placentation include trophoblast invasion, degradation and remodelling of the uterine decidual extracellular matrix, and apoptosis without thrombosis. We tested this hypothesis by analysing the effect of functional polymorphisms in the genes coding for MMP9, MMP3 and annexin A5 on the risk of preeclampsia using a case-control design. In 163 women with preeclampsia and 163 controls we studied the association with polymorphisms in the MMP9 (-1562 C/T), MMP3 (-1612 5A/6A) and annexin A5 (-1 C/T) genes using logistic regression analysis. A lower prevalence of the rare T allele of the MMP9 (-1562 C/T) polymorphism in women with preeclampsia was found (odds ratio 0.48, 95% confidence interval 0.25-0.90). The distribution of the MMP3 (-1612 5A/6A) and annexin A5 (-1 C/T) gene polymorphisms were similar in cases and controls. Our results suggest that the MMP9-1562T allele is associated with a reduced risk of preeclampsia and therefore may protect against maladaptation of the spiral arteries and decreased decidual degradation. The elevated MMP9 concentrations reported to be associated with the -1562T allele might be essential for the development of an adequate maternal-fetal interface early in pregnancy by facilitating trophoblast apoptosis and degradation.

Thrombophilia and Adverse Pregnancy Outcome

This article focuses on the clinical evaluation and management of women who have thrombophilia-related placental vascular complications, including fetal loss, pre-eclampsia, intrauterine fetal growth restriction, and placental abruption. All are major causes of maternal and fetal adverse outcomes.

Evaluation of Factor V Leiden, Prothrombin and Methylenetetrahydrofolate Reductase Gene Mutations in Patients with Severe Pregnancy Complications in Northern Finland

BACKGROUND

Thrombosis in placenta may lead to severe pregnancy complications. Most important inherited thrombophilias are factor V Leiden mutation, prothrombin mutation, and methylenetetrahydrofolate reductase mutation. The aim of our research was to evaluate the prevalence of inherited thrombophilias in severe pregnancy complications and in normal pregnancies.

MATERIAL AND METHODS

The study subjects with severe preeclampsia, intrauterine growth restriction, placental abruption or fetal death were collected during the period 1999-2004 from Oulu University Hospital. We also collected during the same period voluntary parturients with normal pregnancy outcome as the control group. FVL, FII, and MTHFR gene mutations of the patients and controls were analyzed.

RESULTS

We found a significant difference in the prevalence of FVL mutation between the groups. There were 9.5% FVL mutations in the study group compared to 1.8% in the control group; the observed difference between prevalences was 7.7% (95% CI 2.0-13.4). No statistical difference was found in the FII or MTHFR mutations between the groups. All FV and FII mutations were heterozygous and all the MTHFR mutations homozygous.

CONCLUSION

Women with thrombophilia have a risk for severe pregnancy complications. Randomized controlled trials are needed to assess the influence of low-molecular-weight heparin in pregnant women with thrombophilia.

Gender-specific association of the factor V Leiden mutation with fertility and fecundity in a historic cohort. The Leiden 85-Plus Study

BACKGROUND

Factor V Leiden (FVL, Arg506Gln) mutation may facilitate embryo implantation and increase fertility and fecundity. This was studied in subjects who were of childbearing age in a time with minimal fertility control without modern contraceptive methods.

METHODS

From 1986 to 1999, 1502 inhabitants of Leiden, The Netherlands, reaching the age of 85 years were enrolled in the Leiden 85-Plus Study. Of 1176 subjects the FVL status was analysed, in 365 male and 811 female subjects.

RESULTS

The FVL carrier rate was 4.3%. Fertility was not affected by FVL status. In male subjects, fecundity (interval between marriage and birth of first child) was significantly increased in FVL carriers; 67% of male FVL carriers had a child within 371 days of marriage (therefore conceived within 3 months of marriage), compared with 19% of male non-carriers [relative risk (RR), 3.5; 95% confidence interval (CI), 2.1-5.7; P < 0.001]. Within 6 months of marriage, 75% of male FVL carriers had conceived a child compared with 34% male non-carriers (RR, 2.2; 95% CI, 1.5-3.2; P = 0.01). In female subjects, fecundity was not influenced by FVL status.

CONCLUSION

Fecundity is increased in male FVL carriers; in female subjects, no such association was observed.

Quantitative distribution of a panel of circulating mRNA in preeclampsiaversus controls

OBJECTIVE

The aim of this study was to evaluate whether the quantitative distribution of a panel of circulating mRNAs from maternal whole blood of normal pregnancies is statistically different from those complicated with preeclampsia (PE) with or without intrauterine growth restriction (IUGR).

METHODS

Maternal whole blood of six subjects with mild or severe PE with or without IUGR and 30 matched controls (1:5 match for gestational age) were retrospectively examined for circulating mRNA markers. Seven specific mRNA markers were identified and chosen based on previous microarray mRNA expressions performed on placental tissue from normal and PE patients. They were human placental lactogen (hPL), inhibin A, KISS-1, pregnancy-associated plasma protein-A (PAPP-A), plasminogen activator inhibitor type 1 (PAI-1), selectin-P and vascular endothelial growth factor receptor (VEGFR), which were therefore quantified for statistical purposes.

RESULTS

Median gestational age was 229 (178-283) and 232 (194-262) days for controls and cases respectively. All mRNA markers but PAPP-A, showed statistically different median values. They were hPL, inhibin A, KISS-1, PAI-1, Selectin-P, and VEGFR. Inhibin A, Selectin-P and VEGFR showed higher values than expected for controls. Instead, hPL, KISS-1 and PAI-1 values of PE patients were lower than those of controls. Selectin-P was the marker with the most aberrant difference, followed by VEGFR and KISS-1.

CONCLUSION

This preliminary analysis revealed that the median values of a panel of mRNAs from the maternal blood of PE patients were different from those of the same gestational age control group at the third trimester. If prospective studies at the second trimester could detect a related marker sufficiently able to discriminate between affected and unaffected patients and thus detect the disease before its clinical onset, then a screening project using a panel of mRNAs would be feasible.

Thrombophilia in pregnancy: a systematic review

Growing evidence suggests that thrombophilia is associated with venous thromboembolism (VTE) and adverse pregnancy outcomes. However, methodological limitations have made it difficult to obtain a clear overview of the overall risks. We conducted a systematic review to determine the risk of VTE and adverse pregnancy outcomes associated with thrombophilia in pregnancy. The effectiveness of prophylactic interventions during pregnancy was also evaluated. Major electronic databases were searched, relevant data abstracted and study quality assessed by two independent reviewers. Odds ratios (ORs) stratified by thrombophilia type were calculated for each outcome. A total of 79 studies were included in our review. The risks for individual thrombophilic defects were determined for VTE (ORs, 0.74-34.40); early pregnancy loss (ORs, 1.40-6.25); late pregnancy loss (ORs, 1.31-20.09); pre-eclampsia (ORs, 1.37-3.49); placental abruption (ORs, 1.42-7.71) and intrauterine growth restriction (ORs, 1.24-2.92). Low-dose aspirin plus heparin was the most effective in preventing pregnancy loss in thrombophilic women (OR, 1.62). Our findings confirm that women with thrombophilia are at risk of developing VTE and complications in pregnancy. However, despite the increase in relative risk, the absolute risk of VTE and adverse outcomes remains low. There is also a lack of controlled trials of antithrombotic intervention to prevent pregnancy complications. Thus, at present, universal screening for thrombophilia in pregnancy cannot be justified clinically.

Thrombophilia Is Significantly Associated With Severe Preeclampsia

The role of thrombophilia in the pathogenesis of preeclampsia is controversial. The aim of this case-controlled study was to determine whether thrombophilia increases the risk of preeclampsia or interferes with its clinical course. A total of 808 white patients who developed preeclampsia (cases) and 808 women with previous uneventful pregnancies (controls) matched for age and parity were evaluated for inherited and acquired thrombophilia (factor V Leiden; factor II G20210A; methylenetetrahydrofolate reductase C677T; protein S, protein C, and antithrombin III deficiency; anticardiolipin antibodies; lupus anticoagulant; and hyperhomocysteinemia). Odds ratios (ORs) with 95% confidence intervals (CIs) for risk of being carriers of thrombophilia in cases compared with controls and for risk of maternal life-threatening complications and adverse perinatal outcomes in preeclamptic patients with or without thrombophilia were calculated. Women with severe preeclampsia (406 cases) had a higher risk (OR, 4.9; 95% CI, 3.5 to 6.9) of being carriers of either an inherited or acquired thrombophilic factor, except for protein S, protein C, and antithrombin deficiency. In women with mild preeclampsia (402 cases), only prothrombin and homozygous methylenetetrahydrofolate reductase gene mutations were significantly more prevalent than in the controls. Thrombophilic patients with severe preeclampsia are at increased risk of acute renal failure (OR, 1.8; 95% CI, 1.5 to 2.2), disseminated intravascular coagulation (OR, 2.7; 95% CI, 1.1 to 6.4), abruptio placentae (OR, 2.6; 95% CI, 1.2 to 6.0) and perinatal mortality (OR, 1.7; 95% CI, 1.5 to 2.2) compared with nonthrombophilic preeclamptic patients. Our study demonstrates a significant association between maternal thrombophilia and severe preeclampsia in white women. Thrombophilia also augments the risk of life-threatening maternal complications and adverse perinatal outcomes in preeclamptic patients.

Thrombophilia and pregnancy outcomes

Pregnancy complications are still a challenge for physicians, because knowledge of pathomechanisms and prophylactic measures is still limited. In recent years thrombophilia as a risk factor for pregnancy complications has gained much attention in the scientific community. However, data on this topic in the literature are conflicting. Besides an established association between antiphospholipid antibodies and pregnancy loss, available data suggest additional associations for antithrombin deficiency, hyperhomocysteinemia and also for factor (F)V Leiden, prothrombin G20210A variation, and protein S-deficiency. The contribution of thrombophilia to the risk of pre-eclampsia is less well established and recent studies did not confirm earlier data suggesting an association between thrombophilia and pre-eclampsia. A limited number of prospective studies have failed to reveal an increased risk of pregnancy complications in unselected women with thrombosis risk factors. Low-molecular weight heparin (LMWH) seems to have a positive effect on pregnancy outcome after single or recurrent abortions, however, data from only one controlled trial are available. Experience in the prevention of pre-eclampsia by prophylactic heparin is very limited, and in addition, data on pregnancy complications in women with known heritable thrombophilia or a history of thrombosis are inconsistent. These women will usually have a favorable pregnancy outcome referring to the European Prospective Cohort on Thrombophilia Study. In conclusion, thrombophilia screening might be justified in women with pregnancy loss and treatment with LMWH might be considered in those with pregnancy loss and thrombophilia. Further prospective studies and controlled interventional trials are urgently needed.

Inherited thrombophilias and adverse pregnancy outcome: screening and management

Inherited thrombophilias are a heterogenous group of conditions which have been implicated in a variety of pregnancy complications. Evidence is mounting that implicates these inherited disorders in a range of pregnancy outcomes, including recurrent miscarriage, late fetal loss, preeclampsia, abruptio placentae, and intrauterine growth restriction. The most commonly identified inherited thrombophilias consist of Factor V Leiden and the prothrombin gene mutation G20210A. Rarer inherited thrombophilic conditions include deficiencies of protein S, C and antithrombin. More recently, deficiency of protein Z has been linked to pregnancy complications, including preterm delivery. Clinical manifestations often are associated with the presence of more than one inherited thrombophilia, consistent with their multigenic nature. Some, but not all, studies investigating the use of heparin to prevent adverse pregnancy outcome have demonstrated a benefit. However, an adequate randomized trial is required to definitively determine whether heparin anticoagulation is the best prevention option in patients who harbor one or more inherited thrombophilias and are at risk for adverse pregnancy outcome. This review will summarize the association of thrombophilic conditions and obstetrical complications.

A systematic review of the association between factor V Leiden or prothrombin gene variant and intrauterine growth restriction

OBJECTIVE

The purpose of this study was to conduct a systematic review of the literature of studies that examined the association between factor V Leiden and/or prothrombin gene variant and intrauterine growth restriction.

STUDY DESIGN

This systematic review of studies assesses the association between factor V Leiden and/or prothrombin gene variant and intrauterine growth restriction.

RESULTS

Ten case-control studies fulfilled the selection criteria for inclusion in the meta-analysis. There was a significant association between factor V Leiden and intrauterine growth restriction (odds ratio, 2.7; 95% CI, 1.3-5.5) and prothrombin gene variant and intrauterine growth restriction (odds ratio, 2.5; 95% CI, 1.3-5.0). Five cohort studies were identified in the systematic review; 3 studies were prospective (2 full publications), and 2 studies were retrospective (1 full publication). Combining the 2 full publication prospective studies yields a summary relative risk of 0.99 (95% CI, 0.5-1.9).

CONCLUSION

This meta-analysis of case-control studies suggests that the factor V Leiden and prothrombin gene variant both confer an increased risk of giving birth to an intrauterine growth restricted infant, although this may be driven by small, poor-quality studies that demonstrated extreme associations. Large well-conducted prospective cohort studies are required to determine definitively whether an association between thrombophilia and intrauterine growth restriction is present.

Genetic thrombophilias and preeclampsia: a meta-analysis

OBJECTIVE

To assess the relationship between the factor V Leiden (1691 G-A) single nucleotide polymorphism (SNP), the methylene tetrahydrofolate reductase (MTHFR) 677 C-T SNP, and the prothrombin 20210 G-A SNP and the risk of preeclampsia, by conducting a meta-analysis of all case-control studies with data on these polymorphisms and the risk of preeclampsia.

DATA SOURCES

MEDLINE (1966 to November 2002), EMBASE (1980 to November 2002). Search terms included "preeclampsia," "thrombophilia," "factor V Leiden," "protein C," "MTHFR," "methylenetetrahydrofolate reductase," "homocysteine," and "prothrombin gene 20210."

METHODS OF STUDY SELECTION

Case-control studies of genetic thrombophilias and preeclampsia were included.

TABULATION, INTEGRATION, AND RESULTS

We identified 349 titles and reviewed 47 articles for inclusion and exclusion criteria. Thirty-one studies with 7,522 patients were included in the meta-analysis. Data from patients characterized as having severe preeclampsia were extracted and analyzed separately. The pooled odds ratio (OR) for the association of factor V Leiden and all cases of preeclampsia was 1.81 (95% confidence interval [CI] 1.14-2.87) and 2.24 (95% CI 1.28-3.94) for cases of severe preeclampsia. The pooled OR for the MTHFR 677 TT genotype and all preeclampsia was 1.01 (95% CI 0.79-1.29) and 1.38 (95% CI 0.93-2.06) for severe preeclampsia. The OR for the prothrombin 20210 polymorphism and all preeclampsia was 1.37 (95% CI 0.72-2.57) and 1.98 (.94-4.17) for severe preeclampsia.

CONCLUSION

This meta-analysis suggests that the factor V Leiden SNP is associated with an increased risk of preeclampsia. Further studies are warranted to determine whether subgroups of high-risk women should be screened for this mutation.

Thrombophilies et pathologies vasculaires placentaires. Revue de la littérature

PURPOSE

Hereditary thrombophilia as antiphospholipid syndrome (APS) may represent a new risk factor for placental vascular diseases.

CURRENT KNOWLEDGE AND KEY POINTS

General screening for biological abnormalities related to thrombophilia is poorly associated with placental vascular diseases and therefore, may be unwarranted. Women with an history of thrombotic diseases may be at risk for late fetal loss or preeclampsia. Adverse obstetric outcomes are particularly high despite anticoagulation regimens in patients with APS. A high frequency for biological abnormalities related to thrombophilia was detected in pregnancies complicated by late fetal loss in comparison with controls. However, no beneficial strategy prevention was clearly reported and therefore, a selective testing was actually debated for these patients.

FUTURE PROSPECTS AND PROJECTS

Searching for acceptable treatment alternatives in patients with APS in order to reduce the high rate for pregnancy complications which may be persistent despite anticoagulation regimens. To determine by controlled studies the role for a prophylactic low molecular weight heparin regimens in patients with haemostatic abnormalities and previous pregnancy complications.