Thromboprophylaxis and pregnancy outcomes in asymptomatic women with inherited thrombophilias

Factor V Leiden G1691A and Prothrombin Gene G20210A Mutations on Pregnancy Outcome

Factor V Leiden (FVL) G1619A mutation and prothrombin gene (PTG) G20210A are the most common inherited thrombophilias. They have been associated with various obstetric complications such as venous thromboembolism, recurrent pregnancy loss, preeclampsia, abruptio placentae, and small for gestational age fetus. The prevalence of these two mutations is 3-15% in Caucasians and is assumed to be far less common in other ethnic populations. However, there have been several controversies regarding advising routine screening of these thrombophilias because of a widely variable strength of association between different ethnic groups, as well as contradictory conclusions by different studies in regards to the association. In this study, the literature was analyzed thoroughly for the effect of FVL G1619A and PTG G20210A mutations on various obstetric outcomes. A review of multiple case-control and prospective studies suggests that despite the availability of robust data on this subject the results remain inconclusive and insubstantial. Further superior quality research, preferably prospective studies, is warranted to conclusively establish this relationship and to enable practitioners to follow a definitive protocol in the screening of various populations for these mutations to achieve an improved pregnancy outcome.

Factor V Leiden, prothrombin G20210A, and methylene tetrahydrofolate reductase mutations and stillbirth: the Stillbirth Collaborative Research Network

BACKGROUND

An evaluation for heritable thrombophilias is recommended in the evaluation of stillbirth. However, the association between thrombophilias and stillbirth remains uncertain.

OBJECTIVE

We sought to assess the association between maternal and fetal/placental heritable thrombophilias and stillbirth in a population-based, case-control study in a geographically, racially, and ethnically diverse population.

STUDY DESIGN

We conducted secondary analysis of data from the Stillbirth Collaborative Research Network, a population-based case-control study of stillbirth. Testing for factor V Leiden, prothrombin G20210A, methylene tetrahydrofolate reductase C677T and A1298C, and plasminogen activating inhibitor (PAI)-1 4G/5G mutations was done on maternal and fetal (or placental) DNA from singleton pregnancies. Data analyses were weighted for oversampling and other aspects of the design. Odds ratios (OR) were generated from univariate models regressing stillbirth/live birth status on each thrombophilia marker.

RESULTS

Results were available for ≥1 marker in 488 stillbirths and 1342 live birth mothers and 405 stillbirths and 990 live birth fetuses. There was an increased odds of stillbirth for maternal homozygous factor V Leiden mutation (2/488; 0.4% vs 1/1380; 0.0046%; OR, 87.44; 95% confidence interval, 7.88-970.92). However, there were no significant differences in the odds of stillbirth for any other maternal thrombophilia, even after stratified analyses. Fetal 4G/4G PAI-1 (OR, 0.63; 95% confidence interval, 0.43-0.91) was associated with decreased odds of stillbirth. Other fetal thrombophilias were similar among groups.

CONCLUSION

Most maternal and fetal thrombophilias were not associated with stillbirth. Maternal factor V Leiden was weakly associated with stillbirth, and the fetal PAI-1 4G/4G polymorphism was associated with live birth. Our data do not support routine testing for heritable thrombophilias as part of an evaluation for possible causes of stillbirth.

Genetic Risk Factors in Venous Thromboembolism

Genetic risk factors predispose to thrombophilia and play the most important etiopathogenic role in venous thromboembolism (VTE) in people younger than 50 years old. At least one inherited risk factor could be found in about half of the cases with a first episode of idiopathic VTE.Roughly, genetic risk factors are classified into two main categories: loss of function mutations (such as deficiencies of antithrombin, protein C, protein S) and gain of function mutations, (such as prothrombin mutation G20210A, factor V Leiden). A revolutionary contribution to the genetic background of VTE was brought by the achievements of the genome-wide association studies which analyze the association of a huge number of polymorphisms in large sample size.Hereditary thrombophilia testing should be done only in selected cases. The detection of hereditary thrombophilia has impact on the management of the anticoagulation in children with purpura fulminans, pregnant women at risk of VTE and may be useful in the assessment of the risk for recurrent thrombosis in patients presenting an episode of VTE at a young age (<40 years) and in cases with positive family history regarding thrombosis.

Activated protein C resistance and antiphospholipid antibodies in recurrent fetal loss: experience of a single referral center in northern iraq

The current study was initiated to determine the prevalence of activated protein C (APC) resistance, factor V Leiden and antiphospholipid antibodies (APA) in Iraqi women with recurrent fetal loss (RFL), and evaluate the outcome of intervention in those with such states. For this purpose a total of 103 Iraqi women referred to a major teaching hospital in Northern Iraq with two or more consecutive fetal losses, as well as 100 age matched women with no history of fetal loss and at least one live birth were enrolled. After appropriate clinical evaluation, the enrolled subjects were tested for APA as well as APC resistance. Subjects who were APC resistant were further tested for factor V Leiden mutation using a polymerase chain reaction and reverse hybridization. Patients with documented APA and/or with APC resistance, were put on low dose aspirin with or without low molecular weight heparin during pregnancy, and followed for a minimum of 5 years. The results revealed that among patients' group, APA were detected in 19.4 % compared to 1.0 % of the controls (OR 23.9, p = 0.00005). On the other hand, APC resistance was documented in 9.7 % compared to 1.0 % of the controls (OR 10.6, p = 0.01). Factor V Leiden was detected in 3.9 % of patients and 1 % of the controls (p = 0.38). Among 17 patients with APA available for follow up, there were 24 pregnancies, 18 of which ended with live births (75 %). While among the ten patients who had factor V Leiden or were APC resistant non-carriers, there were 13 pregnancies, 12 ended with live births (92.3 %). In conclusion, this study has demonstrated that among the enrolled Iraqi women, APA and APCR and not factor V Leiden were significantly associated with RFL, and that treatment with aspirin (with or without low molecular weight heparin) had lead to live births in 80.6 % of pregnancies.

Neurocritical care complications of pregnancy and puerperum

Neurocritical care complications of pregnancy and puerperum such as preeclampsia/eclampsia, hemolysis, elevated liver enzymes, low platelets syndrome, thrombotic thrombocytopenic purpura, seizures, ischemic and hemorrhagic stroke, postpartum angiopathy, cerebral sinus thrombosis, amniotic fluid emboli, choriocarcinoma, and acute fatty liver of pregnancy are rare but can be devastating. These conditions can present a challenge to physicians because pregnancy is a unique physiologic state, most therapeutic options available in the intensive care unit were not studied in pregnant patients, and in many situations, physicians need to deliver care to both the mother and the fetus, simultaneously. Timely recognition and management of critical neurologic complications of pregnancy/puerperum can be life saving for both the mother and fetus.

Recurrent cerebral ischaemia in a pregnant woman with patent foramen ovale II° and thrombophilia

This case report concerns a pregnant multipara (age: 27 years) in the 16th gestational week. She developed a sudden onset of paraesthesia in her left lower arm although injecting dalteparin 5000 IU once daily subcutaneously (s. c.) due to a heterozygous factor V Leiden mutation and a prior miscarriage in the first pregnancy and preeclampsia in her third pregnancy. After the miscarriage she delivered two healthy children under prophylactic anticoagulation with low molecular weight heparin (LMWH). Now via magnetic resonance imaging (MRI) she was diagnosed as having multiple cerebral ischaemic lesions. Further workup revealed the presence of a patent foramen ovale (PFO) II° but no venous thrombosis in her legs. She was then treated with dalteparin 5000 IU twice daily by subcutaneous injections. At 19th gestational week she developed paraesthesia in her left lower arm again. The MRI showed a cortical lesion in the territory of the right median cerebral artery. The anticoagulation dose was increased stepwise under surveillance of the anti-FXa-level 3-4 h after subcutaneous injections aiming to achieve the supratherapeutic range of 1.2-1.5 IU/ml anti-Xa-units. No more neurological symptoms appeared under this antithrombotic therapy. The patient delivered by induction of labor at the 38th gestational week.

Review of Management and Outcomes in Women with Thrombophilia Risk during Pregnancy at a Single Institution

Pregnancy is a hypercoagulable state associated with an increased risk of venous thromboembolic disease (VTE). We retrospectively studied 38 Caucasian pregnant women with thrombophilia risk and compared their obstetric outcomes with a matched cohort without known thrombophilia risk during the period between January 2007 and December 2010. There were (2) cases with factor V Leiden, (6) prothrombin gene mutation, (1) antithrombin III deficiency, (2) protein C deficiency, (3) protein S deficiency, (10) MTHFR mutation, (7) anti-cardiolipin antibodies, and (1) lupus anticoagulant. Patients without thrombophilia who presented with recurrent unprovoked VTE were considered as high risk (6 cases). Most patients received anticoagulation (34/38) with aspirin only (6), enoxaparin (27), and warfarin (1). Twenty-six out of thirty-eight pregnant women (68.4%) with an increased risk of thrombophilia experienced one or more obstetric complications defined as hypertension, preeclampsia, placenta abruptio, VTE, and oligohydramnios, compared with 15 out of 40 (37.5%) pregnant women in the control group (OR 3.6; 95% CI 1.42, 9.21, P < 0.001). The incidence of obstetric complications was significantly higher in the thrombophilia group compared to the controls. However, these complications were the lowest among patients who received full-dose anticoagulation. Our study suggests that strict application of anticoagulation therapy for thrombophilia of pregnancy is associated with an improved pregnancy outcome. The study was registered in the Australian and New Zealand Clinical Trials Registry under ACTRN12612001094864.

The role of thrombophilia in pregnancy

Thrombotic disease is a major cause of peripartum morbidity and mortality worldwide. Development of thrombosis in pregnancy is multifactorial due to the physiologic changes of pregnancy—which induce a relative hypercoagulable state—as well as physical changes leading to increased stasis and also the effects of both the inherited and the acquired thrombophilias. In this review, we discuss the impact of each of these factors on the development of thrombosis as well as the evidence for the impact of pregnancy-associated thrombosis on pregnancy outcome. We then discuss the use of both prophylactic and therapeutic anticoagulation during pregnancy and the puerperium. We review the indications and dosing recommendations for administration of anticoagulation in a context of discussing the evidence including the lack of evidence and formal guidelines in this area. We briefly address the role of the new oral anticoagulants in pregnancy and conclude that significant further research in women with thrombophilias and pregnancy-associated thrombosis may help clarify the management of this condition in the future.

Inherited thrombophilia: diagnosis and anticoagulation treatment in pregnancy

The association between inherited thrombophilia and deep vein thrombosis is well established. Adverse pregnancy outcomes, sometimes called placenta-mediated complications, have been attributed to excessive thrombosis and inflammation at the uteroplacental interface. This linkage resulted in widespread screening for thrombophilia in women with adverse pregnancy outcome. Anticoagulant therapy was initially liberally administered for prevention of adverse pregnancy outcome. Well-designed randomized trials were initiated and the results of some of these randomized trials have provided critical evidence-based data to serve as a guide for clinicians faced with managing patients with one or more of the common obstetric complications.

Factor V Leiden thrombophilia

Factor V Leiden is a genetic disorder characterized by a poor anticoagulant response to activated Protein C and an increased risk for venous thromboembolism. Deep venous thrombosis and pulmonary embolism are the most common manifestations, but thrombosis in unusual locations also occurs. The current evidence suggests that the mutation has at most a modest effect on recurrence risk after initial treatment of a first venous thromboembolism. Factor V Leiden is also associated with a 2- to 3-fold increased relative risk for pregnancy loss and possibly other obstetric complications, although the probability of a successful pregnancy outcome is high. The clinical expression of Factor V Leiden is influenced by the number of Factor V Leiden alleles, coexisting genetic and acquired thrombophilic disorders, and circumstantial risk factors. Diagnosis requires the activated Protein C resistance assay (a coagulation screening test) or DNA analysis of the F5 gene, which encodes the Factor V protein. The first acute thrombosis is treated according to standard guidelines. Decisions regarding the optimal duration of anticoagulation are based on an individualized assessment of the risks for venous thromboembolism recurrence and anticoagulant-related bleeding. In the absence of a history of thrombosis, long-term anticoagulation is not routinely recommended for asymptomatic Factor V Leiden heterozygotes, although prophylactic anticoagulation may be considered in high-risk clinical settings. In the absence of evidence that early diagnosis reduces morbidity or mortality, decisions regarding testing at-risk family members should be made on an individual basis.

Impact of common thrombophilias and JAK2 V617F on pregnancy outcomes in unselected Italian women

BACKGROUND

Although an association between thrombophilias and adverse pregnancy outcome has been shown, the influence of the most common inherited thrombophilias and the somatic mutation JAK2 V617F in determining an adverse outcome is questioned.

OBJECTIVES

We examined the contribution of the factor V Leiden (FVL), the prothrombin G20210A (PTm) and the somatic JAK2 V617F mutations to adverse pregnancy outcome in an unselected cohort of pregnant women.

PATIENTS/METHODS

During the study period, 5345 pregnant women were admitted to the 14 hospitals of the five provinces of the Campania region (Italy). Of these, 3097 samples were investigated and obstetric history collected. The presence of the FVL, PTm, and JAK2 V617F mutation was prospectively determined by polymerase chain reaction followed by TaqMan SNP genotyping assays.

RESULTS AND CONCLUSIONS

We identified 119 (3.8%) women that carried FVL and 138 (4.4%) with the PTm. Only 4 (0.1%) women carried both mutations. Only one woman tested positive for the JAK2 V617F somatic mutation. The prevalence of a previous history of an adverse pregnancy outcome was similar in women with common thrombophilias as compared to those without. In the current pregnancy, there was no association of any of the genetic markers considered with any of the adverse outcomes investigated. Carriership of FVL or PTm showed a positive trend with delivery of a small for gestational age newborn (OR: 1.5, 95% CI: 0.9-2.5). Pregnancy outcomes in asymptomatic women with inherited thrombophilias are often uneventful. Therefore, in women at low-risk of an adverse pregnancy, neither screening for common thrombophilias nor administration of routine thromboprophylaxis are warranted.

Thrombophilias and stillbirth

It is often postulated that both inherited and acquired thrombophilias increase the risk of stillbirth. In an attempt to reduce this theoretical risk, pregnant patients with prior fetal losses and thrombophilias are anticoagulated. However, there is no definitive proof that thrombophilias are causally linked to stillbirth. Prospective studies have failed to establish a definitive link between inherited thrombophilias and stillbirth. The extant literature suggests that only high concentrations of antiphospholipid antibodies are associated with stillbirth. Moreover, when pregnant women with prior fetal losses even in these cases are placed on anticoagulation, it is unclear that their recurrence risk of stillbirth decreases.

Prothrombin gene G20210A mutation and obstetric complications

OBJECTIVE

To estimate whether maternal carriage of the prothrombin gene G20210A mutation is associated with pregnancy loss, preeclampsia, placental abruption, or small for gestational age (SGA) neonates in a low-risk, prospective cohort.

METHODS

This was a secondary analysis of the Eunice Kennedy Shriver National Institute of Child Health and Human Development factor V Leiden study, a multicenter, prospective, observational cohort of 5,188 unselected singleton gestations. A total of 4,167 first-trimester samples were available for analysis and were tested for the prothrombin G20210A mutation. Obstetric complications were compared between women with and without the prothrombin G20210A mutation by univariable and multivariable analysis.

RESULTS

A total of 157 (3.8%) women had the prothrombin gene mutation (156 heterozygous and one homozygous). Carriers of the prothrombin G20210A mutation had similar rates of pregnancy loss, preeclampsia, SGA neonates, and abruption compared with noncarriers. Results were similar in a multivariable analysis controlling for age, race, prior pregnancy loss, prior SGA neonates, and family history of thromboembolism. Three thromboembolic events occurred in women testing negative for the mutation.

CONCLUSION

There was no association between the prothrombin G20210A mutation and pregnancy loss, preeclampsia, abruption, or SGA neonates in a low-risk, prospective cohort. These data raise questions about the practice of screening women without a history of thrombosis or adverse pregnancy outcomes for this mutation.

LEVEL OF EVIDENCE

II.