Risk of venous thrombosis in pregnancy among carriers of the factor V Leiden and the prothrombin gene G20210A polymorphisms

To Test or Not to Test: Routine Thrombophilia Diagnostic Screening of Women with Reproductive Failures

BACKGROUND

Recurrent reproductive failure is a global health issue affecting a significant number of women. Thrombophilias have been implicated as a possible cause. Inherited thrombophilias include a single nucleotide variant on factor V Leiden and prothrombin.

OBJECTIVE

The aim of this study was to evaluate the association between the following single nucleotide variants: factor V Leiden (c.1601G>A), the prothrombin gene (c.*97G>A) and the reproductive failure in the Polish population.

METHODS

The study was conducted in a group of 545 patients with recurrent pregnancy loss, RPL (≥2 miscarriages), and in a group of 641 patients with infertility. The distribution of genotypes for the selected variants were determined by RFLP-PCR and by the real-time PCR method.

RESULTS

A variant of the F5 gene was found in 5.14% of patients with RPL and in 6.08% of infertile women. A variant of the F2 gene was identified in 0.73% of patients with RPL and in 2.03% of women with infertility. The frequency in the study groups did not differ from that in the general population. No association between the studied variants of the F5 gene or the F2 gene and the predisposition to reproductive wastage was found.

CONCLUSIONS

Recommendations for routine thrombophilia testing in women with recurrent miscarriages should be revisited. The decision regarding testing should be made individually depending on additional factors indicating an increased risk of venous thromboembolism.

Thrombophilia, Thrombosis and Thromboprophylaxis in Pregnancy: For What and in Whom?

Compared with nonpregnant women, pregnancy carries a four- to fivefold higher risk of venous thromboembolism (VTE). Despite increasing use of heparin prophylaxis in identified high-risk patients, pulmonary embolism still is the leading cause of maternal mortality in the western world. However, evidence on optimal use of thromboprophylaxis is scarce. Thrombophilia, the hereditary or acquired tendency to develop VTE, is also thought to be associated with complications in pregnancy, such as recurrent miscarriage and preeclampsia. In this review, the current evidence on optimal thromboprophylaxis in pregnancy is discussed, focusing primarily on VTE prevention strategies but also discussing the potential to prevent recurrent pregnancy complications with heparin in pregnant women with thrombophilia.

Prevention of Venous Thromboembolism during Pregnancy and the Puerperium with a Special Focus on Women with Hereditary Thrombophilia or Prior VTE-Position Paper of the Working Group in Women's Health of the Society of Thrombosis and Haemostasis (GTH)

Venous thromboembolism (VTE) is a major cause of maternal morbidity during pregnancy and the postpartum period. Because there is a lack of adequate study data, management strategies for the prevention of VTE during pregnancy have mainly been deduced from case-control and observational studies and extrapolated from recommendations for non-pregnant patients. The decision for or against pharmacologic thromboprophylaxis must be made on an individual basis weighing the risk of VTE against the risk of adverse side effects such as severe bleeding complications. A comprehensive, multidisciplinary approach is often essential as the clinical scenario is made more complex by the specific obstetric context, especially in the peripartum period. As members of the Working Group in Women's Health of the Society of Thrombosis and Haemostasis (GTH), we summarize the evidence from the available literature and aim to establish a more uniform strategy for VTE risk assessment and thromboprophylaxis in pregnancy and the puerperium. In this document, we focus on women with hereditary thrombophilia, prior VTE and the use of anticoagulants that can safely be applied during pregnancy and the lactation period.

Low molecular weight heparins use in pregnancy: a practice survey from Greece and a review of the literature

Background

Use of LMWH in pregnancy is not only limited to VTE management, but it extends, to the management of vascular gestational complications and the optimization of IVF pregnancies despite the lack of concrete scientific evidence. In this context, we conducted the present study aiming to gain insights regarding the use of LMWH during pregnancy and puerperium. We recorded indication for use, diagnostic work-up as well as the safety and efficacy of the treatment, trying to elucidate the clinical practice in our country.

Methods

We analyzed data regarding 818 pregnant women received LMWH during 2010-2015.Our cohort had a median age of 33.9 years and a BMI of 23.6.There were 4 groups: those with a history of VTE [Group-A: 76], those with pregnancy complications [Group-B: 445], those undergoing IVF [Group-C: 132] and those carrying prothrombotic tendency (thrombophilia, family history of VTE, other) [Group-D: 165]. Mean duration of LMWH administration was 8.6 ± 1.5 months. Out of the total number, 440 received LMWH in fixed prophylactic dose, 272 in higher prophylactic-weight adjusted dose and 106 in therapeutic dose. Moreover, 152 women received in addition low-dose acetylsalicylic acid (ASA). 93.8% of pregnancies were single and 6.2% were multiple ones. Live births occurred in 98.7% of pregnancies.

Results

Anticoagulation was efficacious and well tolerated. Seventeen VTE events were recorded; 7 of them antepartum and 10 postpartum. No major bleeding events were observed while 13 clinical relevant non-major bleeding events were recorded. Regarding gestational vascular complications, 28 IUGR events were recorded, as well as 48 cases of preterm labor of which 12 were concomitant with IUGR (25%). Six early pregnancy losses were recorded; there were 3 fetal deaths and 3 cases of pre-eclampsia/eclampsia.

Conclusions

LMWHs are used extensively during pregnancy and puerperium in Greece for VTE treatment and prophylaxis and for a variety of other indications as well. Although the drug has been shown to be both safe and efficacious, its use for some indications has no proven scientific evidence. In order to clearly define the role of LMWHs in pregnancy, beyond thromboprophylaxis, large prospective studies are required, which could be based on the conclusions of this study.

Clinical and laboratory manifestations of the prothrombin gene mutation in women of reproductive age

Research objective

To research the association of prothrombin (factor II) activity given the prothrombin G20210A mutation carriage with its clinical manifestations as thrombotic complications.

Materials and methods

A prospective clinical cohort study of 290 women of reproductive age was conducted. Two cohort groups were identified: the study group of 140 patients with prothrombin mutation G20210A genotype and the control group of 150 women with G20210G genotype.

Results

The prothrombin G20210A mutation carriage is associated with the risk of thrombotic complications compared to the wild G20210G type (RR =17.1; p<0.0001) and is characterized by thrombosis localized both in the venous (66.7%) and arterial (33.3%) vascular pools. The threshold value of prothrombin activity (174.8%) for G20210A genotype was calculated, making it possible to conclusively predict the risk of thrombotic events with the accuracy of 90.4%.

Conclusion

The phenotypic manifestation of the prothrombin G20210A mutation in the form of venous and arterial thromboses in women of reproductive age is associated with a super-threshold increase in prothrombin (factor II) activity, which makes it possible to stratify the patients into the group of high risk of thromboses.

Preventing venous thromboembolism during pregnancy and postpartum: crossing the threshold

When should a patient with a known thrombophilia or prior venous thromboembolism (VTE) receive low-molecular-weight heparin (LMWH) prophylaxis during pregnancy and/or the postpartum period? Accurately predicting thrombotic and bleeding risks and knowing what to do with this information is at the heart of decision-making in these challenging scenarios. This article will explore the concept of a risk threshold from clinician and patient perspectives and provide guidance for the use of antepartum and postpartum LMWH prophylaxis in women with a known thrombophilia or prior VTE. Advice for the management of LMWH prophylaxis use around labor and delivery is also reviewed.

Differential haemostatic risk factors for pregnancy-related deep-vein thrombosis and pulmonary embolism

Limited data exist on thrombophilia and the risk of venous thrombosis (VT) during pregnancy and postpartum. The objectives of the present study were to investigate the role of haemostatic risk factors for pregnancy-related VT and their phenotypic expression in deep-vein thrombosis (DVT) and pulmonary embolism (PE). Total 313 cases with objectively verified first time VT and 353 controls were selected from a source population of 377,155 women with 613,232 pregnancies. The adjusted odds ratio (aOR) for pregnancy-related VT was 1.7 (95% confidence interval [CI] 1.1–2.8) for women with factor VIII >90th percentile. The aOR for VT for endogenous thrombin potential and D-dimer values >90thpercentiles were 1.8 (95% CI 1.1–3.0) and 2.1 (95% CI 1.3–3.3), respectively. Factor IX >90thpercentile or free protein S ≤the 5th percentile increased the risk for PE, and the aORs were 2.4 (95% CI 1.1–5.0) and 3.1 (95% CI 1.3–7.2), respectively. Women carrying the factor V Leiden (F5 rs6025) polymorphism, or who had reduced sensitivity to activated protein C (aPC) in the absence of F5 rs6025, had increased risk for DVT, with unadjusted ORs 7.7 (95% CI 4.7–12.7) and 3.5 (95% CI 2.2–5.4), respectively. Women with a history of pregnancy-related VT showed activation of coagulation and had elevated factor VIII. Furthermore, high levels of factor IX and low levels of free protein S were associated with increased risk for PE, whereas aPC resistance and F5 rs6025 were risk factors for DVT and not PE.

Pregnancy, thrombophilia, and the risk of a first venous thrombosis: systematic review and bayesian meta-analysis

Objective To provide evidence to support updated guidelines for the management of pregnant women with hereditary thrombophilia in order to reduce the risk of a first venous thromboembolism (VTE) in pregnancy.Design Systematic review and bayesian meta-analysis.Data sources Embase, Medline, Web of Science, Cochrane Library, and Google Scholar from inception through 14 November 2016.Review methods Observational studies that reported on pregnancies without the use of anticoagulants and the outcome of first VTE for women with thrombophilia were eligible for inclusion. VTE was considered established if it was confirmed by objective means, or when the patient had received a full course of a full dose anticoagulant treatment without objective testing. Results 36 studies were included in the meta-analysis. All thrombophilias increased the risk for pregnancy associated VTE (probabilities ≥91%). Regarding absolute risks of pregnancy associated VTE, high risk thrombophilias were antithrombin deficiency (antepartum: 7.3%, 95% credible interval 1.8% to 15.6%; post partum: 11.1%, 3.7% to 21.0%), protein C deficiency (antepartum: 3.2%, 0.6% to 8.2%; post partum: 5.4%, 0.9% to 13.8%), protein S deficiency (antepartum: 0.9%, 0.0% to 3.7%; post partum: 4.2%; 0.7% to 9.4%), and homozygous factor V Leiden (antepartum: 2.8%, 0.0% to 8.6%; post partum: 2.8%, 0.0% to 8.8%). Absolute combined antepartum and postpartum risks for women with heterozygous factor V Leiden, heterozygous prothrombin G20210A mutations, or compound heterozygous factor V Leiden and prothrombin G20210A mutations were all below 3%. Conclusions Women with antithrombin, protein C, or protein S deficiency or with homozygous factor V Leiden should be considered for antepartum or postpartum thrombosis prophylaxis, or both. Women with heterozygous factor V Leiden, heterozygous prothrombin G20210A mutation, or compound heterozygous factor V Leiden and prothrombin G20210A mutation should generally not be prescribed thrombosis prophylaxis on the basis of thrombophilia and family history alone. These data should be considered in future guidelines on pregnancy associated VTE risk.

Air pollution and venous thrombosis: a meta-analysis

Exposure to air pollution has been linked to cardiovascular and respiratory disorders. However, the effect of air pollution on venous thrombotic disorders is uncertain. We performed a meta-analysis to assess the association between air pollution and venous thrombosis. PubMed, Embase, EBM Reviews, Healthstar, Global Health, Nursing Database, and Web of Science were searched for citations on air pollutants (carbon monoxide, sulfur dioxide, nitrogen dioxide, ozone, and particulate matters) and venous thrombosis. Using a random-effects model, overall risk estimates were derived for each increment of 10 μg/m³ of pollutant concentration. Of the 485 in-depth reviewed studies, 8 citations, involving approximately 700,000 events, fulfilled the inclusion criteria. All the main air pollutants analyzed were not associated with an increased risk of venous thrombosis (OR = 1.005, 95% CI = 0.998–1.012 for PM_2.5; OR = 0.995, 95% CI = 0.984–1.007 for PM₁₀; OR = 1.006, 95% CI = 0.994–1.019 for NO₂). Based on exposure period and thrombosis location, additional subgroup analyses provided results comparable with those of the overall analyses. There was no evidence of publication bias. Therefore, this meta analysis does not suggest the possible role of air pollution as risk factor for venous thrombosis in general population.

Thrombophilic risk of individuals with rare compound factor V Leiden and prothrombin G20210A polymorphisms: an international case series of 100 individuals

The risk of thrombosis in individuals with rare compound thrombophilias, homozygous factor V Leiden (FVL) plus heterozygous prothrombin G20210A (PTM), homozygous PTM plus heterozygous FVL, and homozygous FVL plus homozygous PTM, is unknown. We identified, worldwide, individuals with these compound thrombophilias, predominantly through mailing members of the International Society on Thrombosis and Haemostasis. Physicians were sent a clinical questionnaire. Confirmatory copies of the genetic results were obtained. One hundred individuals were enrolled; 58% were female. Seventy-one individuals had a venous thrombosis (includes superficial and deep vein thrombosis, and pulmonary embolism), 4 had an arterial thrombosis and 6 had both. Nineteen individuals had never had a thrombotic event. Thrombosis-free survival curves demonstrated that 50% of individuals had experienced a thrombotic event by 35 yrs of age, while 50% had a first venous thromboembolic event (VTE; includes all venous thrombosis except superficial thrombosis) by 41 yrs of age; 38.2% of first VTEs were unprovoked. 37% of patients had at least one VTE recurrence. Seventy percent of first pregnancies carried to term and not treated with anticoagulation were thrombosis-free. In conclusion, patients with these rare compound thrombophilias are not exceedingly thrombogenic, even though they have a substantial risk for VTE.

Thrombophilia and venous thromboembolism in pregnancy: a meta-analysis of genetic risk

Three common polymorphic variants, namely Factor V Leiden (FVL), Prothrombin G20210A (PT G20210A) and Methylenetetrahydrofolate Reductase (MTHFR) C677T are candidate genes for venous thromboembolism (VTE) in pregnancy. We performed a literature review and meta-analysis of pertinent genetic association studies (GAS) in pregnancy, to quantify the genetic risk of VTE in pregnancy. We used the model-free approach of generalized odds ratio (ORG) to estimate gene-to-disease association and explored the mode of inheritance using the degree of dominance h index. Twelve case-control GAS studies provided the full genotype distributions for at least one candidate gene to assess the genetic risk. FVL was associated with a significant risk of VTE in pregnancy (ORG 7.28; 95% confidence interval 5.53-9.58) and a dominant mode of inheritance (h=0.76), that is the effect of heterozygous carriers will lie close to the homozygous mutant genotype. PT G20210A mutation was also associated with a significant VTE risk (ORG 5.43; 95% CI 3.66-8.03) and had an over-dominant mode of inheritance (h=1.5), suggesting that the effect of heterozygous carriers may exceed that of homozygous mutant. MTHFR C677T had no association with VTE risk in pregnancy (ORG 1.24; 95% CI 0.88-1.73). Our analysis provided robust data on VTE in pregnancy, relative to FVL and PT G20210A status and suggested that the genetic effects of heterozygous over homozygous carriers do not justify stratification of heterozygous as "lower risk" over homozygous mutants. On clinical grounds this may impact decisions to preferentially exclude heterozygous from anticoagulation prophylaxis.

Association between newborn birth weight and the risk of postpartum maternal venous thromboembolism: a population-based case-control study

BACKGROUND

Postpartum venous thromboembolism (VTE) is a potentially fatal and preventable event leading to substantial short- and long-term morbidity. We sought to evaluate whether the delivery of term newborns of low or high birth weight was associated with greater risks of VTE.

METHODS AND RESULTS

In a population-based case-control study conducted in Washington State from 1987 through 2011, cases of hospitalized VTE within 3 months of delivery were identified by using selected International Classification of Diseases, Ninth Revision, Clinical Modification codes. Controls were randomly selected postpartum women without VTE, matched on birth year. Birth weight and other maternal and pregnancy characteristics were extracted from birth certificate data. Among term live singleton deliveries, we compared the risk of VTE for mothers of newborns of low and high birth weights (<2500 g and >4000 g, respectively) versus mothers of newborns of normal birth weight (2500-4000 g). Logistic regression models were adjusted for maternal age, race, education, body mass index, parity, delivery methods, gestational length, smoking, gestational diabetes mellitus, and preeclampsia. Patients with VTE (n=547) were older, had a higher body mass index, and experienced more pregnancy-related complications than controls (n=9482). In comparison with mothers of newborns with normal birth weight, mothers of newborns with low birth weight had a 3-fold increased risk of VTE, which persisted after multivariable adjustment (odds ratio, 2.98; 95% confidence interval, 1.80-4.93). Mothers of newborns with high birth weight had only a slightly increased risk of VTE, which was attenuated after multivariable adjustment (odds ratio, 1.26; 95% confidence interval, 0.99-1.61).

CONCLUSIONS

The delivery of a newborn with low birth weight is associated with a 3-fold increased risk of maternal postpartum VTE. This should be considered when assessing VTE risk at delivery.

Genetic variations in the annexin A5 gene and the risk of pregnancy-related venous thrombosis

BACKGROUND

Annexin A5 is a natural anticoagulant assumed to have thrombomodulary functions as it shields phospholipid layers from coagulation complexes. It was recently shown that the M2 haplotype within the annexin A5 gene (ANXA5) promoter reduces the transcriptional activity of the gene. In a previous report, the M2 haplotype was found to be associated with pregnancy-related venous thrombosis (VT).

OBJECTIVES

To investigate whether the M1 or M2 haplotypes or other genetic variations in ANXA5 are associated with pregnancy-related VT.

PATIENTS/METHODS

We investigated samples from 313 cases and 353 controls included in the VIP study, which is a case-control study of pregnancy-related VT. We analyzed tag single nucleotide polymorphisms (SNPs) selected from the CEU population (Utah Residents with Northern and Western European Ancestry) of HapMap and the M1 and the M2 haplotypes of the promoter. Odds ratios for VT were calculated for each haplotype with the wild type as the reference and for each tag SNP with the most common genotype as reference.

RESULTS

We did not find any association between genetic variants in ANXA5 and the risk of pregnancy related VT, but some of the genetic variants were not in Hardy-Weinberg equilibrium.

CONCLUSION

Neither the M1/M2 haplotypes nor the tag SNPs in ANXA5 were convincingly associated with pregnancy related VT, but other studies in this field are needed.

Pregnancy and venous thromboembolism: 'TIPPS' for risk stratification

Pregnancy-associated venous thromboembolism (VTE) is a leading cause of maternal mortality, but is relatively uncommon. It is clear that the antepartum and postpartum periods have different magnitudes of risk and distinct risk factors for VTE and therefore must be considered separately. Absolute daily risks of VTE must be understood and explored when deciding to prescribe antepartum or postpartum thromboprophylaxis and must also be balanced against the downsides of prophylaxis. When the risks for VTE and bleeding are both low, other burdens of thromboprophylaxis must be weighed in and a decision made after an individualized patient values- and patient preferences-based discussion. Risk stratification is essential to ensure that the practicing clinician strikes the right balance.

An Altered Treatment Plan Based on Direct to Consumer (DTC) Genetic Testing: Personalized Medicine from the Patient/Pin-cushion Perspective

Direct to consumer (DTC) genomic services facilitate the personalized and participatory aspects of “P4” medicine, but raise questions regarding use of genomic data in providing predictive and preventive healthcare. We illustrate the issues involved by describing a pregnancy management case in which a treatment plan was modified based on a DTC result. A woman whose personal and family history were otherwise unremarkable for thromboembolism learned through DTC testing about the presence of a prothrombin (factor 2) gene mutation (rs1799963). Twice daily injections of enoxaparin were recommended throughout pregnancy for this patient who, without prior knowledge of this mutation, would not have been offered such therapy. Moreover, genetically based medical guidelines are a moving target, and treatment of thrombophilic conditions in asymptomatic patients is controversial. We address the state of the art in actionable personalized medicine with respect to clotting disorders in pregnancy, as well as other factors at play— economics, patient preference, and clinical decision support. We also discuss what steps are needed to increase the utility of genomic data in personalized medicine by collecting information and converting it into actionable knowledge.

Venous thromboembolism associated with pregnancy and hormonal therapy

Venous thromboembolism (VTE) is a major cause of maternal morbidity and mortality during or early after pregnancy and in women taking hormonal therapy for contraception or for replacement therapy. Post-thrombotic syndrome, including leg oedema and leg pain, is an unrecognized burden after pregnancy-related VTE, which will affect more than two of five women. Women with a prior VTE, a family history of VTE, certain clinical risk factors and thrombophilia are at considerably increased risk both for pregnancy-related VTE and for VTE on hormonal therapy. This review critically assesses the epidemiology and risk factors for pregnancy-related VTE and current guidelines for prophylaxis and treatment. We also provide information on the risk of VTE related to hormonal contraception and replacement therapy.

Candidate gene polymorphisms and the risk for pregnancy-related venous thrombosis

Venous thrombosis (VT) is one of the leading causes of maternal death in the western world, but the genetic causes of pregnancy-related VT are insufficiently understood. The aim of this study was to investigate the association between common genetic variations in candidate genes and pregnancy-related VT. We undertook a hospital based case-control study of women with VT during pregnancy or puerperium; controls were women giving birth without having VT. Single nucleotide polymorphisms (SNPs) were selected in 49 pre-specified candidate genes involved in coagulation, inflammation, and hormonal metabolism in 313 cases and 353 controls. We found new associations between SNPs and total pregnancy-related VT in the genes encoding coagulation factors V and VIII, and p-selectin. Additional new associations between SNPs and antenatal VT were found in the genes encoding the epidermal growth factor receptor, the pregnane X receptor, and protein S. Of 21 SNPs previously associated with thrombotic disease, rs2289252 in F11 and rs3917643 in F3 were associated with pregnancy-related VT, while rs4524 in F5 was associated with antenatal VT.