Inherited thrombophilias in pregnant patients: detection and treatment paradigm

Inherited thrombophilias are the leading cause of maternal thromboembolism and are associated with an increased risk of certain adverse pregnancy outcomes including second- and third-trimester fetal loss, abruptions, severe intrauterine growth restriction, and early-onset, severe preeclampsia. Current information suggests that all patients with a history of prior venous thrombotic events and those with these characteristic adverse pregnancy events should be evaluated for thrombophilias. The most common, clinically significant, inherited thrombophilias are heterozygosity for the factor V Leiden and prothrombin G20210A mutations. The autosomal-dominant deficiencies of protein C and protein S are of comparable thrombogenic potential but are far less common. Homozygosity for the 4G/4G mutation in the type-1 plasminogen activator inhibitor gene and the thermolabile variant of the methylenetetrahydrofolate reductase gene, the leading cause of hyperhomocysteinemia, although relatively common, confer a low risk of thrombosis. In contrast, autosomal-dominant antithrombin deficiency and homozygosity or compound heterozygosity (ie, carriers of one copy of each mutant allele) for the factor V and prothrombin mutations are very rare but highly thrombogenic states. Regardless of their antecedent histories, pregnant patients with these highly thrombogenic conditions are at very high risk for both thromboembolism and characteristic adverse pregnancy outcomes, require full therapeutic heparin therapy throughout pregnancy, and need at least 6 weeks of postpartum oral anticoagulation. There is also compelling evidence that patients with the less thrombogenic thrombophilias and a history of venous thrombotic events or characteristic adverse pregnancy outcomes require prophylactic anticoagulant therapy during pregnancy and, in the case of prior thromboembolism, during the puerperium. Antepartum anticoagulation does not appear warranted among patients with less thrombogenic thrombophilias who are without a history of venous thromboembolism, characteristic adverse pregnancy outcomes, or other high risk factors for venous thrombosis.     

Second-trimester maternal serum alpha-fetoprotein (MSAFP) is elevated in women with adverse pregnancy outcome associated with inherited thrombophilias

Obstetric complications, such as severe pre-eclampsia, fetal growth restriction, abruptio placentae, or stillbirth are associated with abnormally elevated second-trimester maternal serum alpha-fetoprotein (MSAFP) and beta subunit of human chorionic gonadotrophin (betahCG). This has been attributed to placental abnormalities. Women with thrombophilias have been shown to have abnormalities of the placenta resulting in adverse pregnancy outcome in these patients. The purpose of the present study was to evaluate whether women with pregnancy complications and inherited thrombophilias have abnormally elevated second-trimester MSAFP or betahCG. Sixty-two women with pregnancy complications were tested for inherited thrombophilias several months after delivery. The thrombophilia group included 29 women with pregnancy complications and an inherited thrombophilia and the control group included 33 other patients without thrombophilia. Patients in the thrombophilia group had a higher median MoM MSAFP compared to the controls (1.337 vs. 1.086, p=0.0516). The incidence of abnormally elevated MSAFP (>2.5 MoM) was also significantly higher in the thrombophilia group compared to controls (21% vs. 3%, p=0.04). Neither the median MoM betahCG nor the incidence of abnormally elevated betahCG were significantly different between the groups. We conclude that second trimester MSAFP, but not betahCG, is abnormally elevated in patients with thrombophilia and obstetric complications.     

Thrombophilias and recurrent miscarriage

Inherited and acquired thrombophilias have been associated with recurrent pregnancy loss. Over recent years our ability to detect protein and genetic abnormalities responsible for thrombotic tendency has improved. We are now left with the task of deciphering which of these thrombophilias carries an increased risk for recurrent pregnancy loss. Acquired thrombophilias including lupus anticoagulant and anticardiolipin antibodies have been linked to recurrent pregnancy loss. However the evidence for the role of inherited thrombophilias such as, heterozygosity for the factor V Leiden, prothrombin G20210A mutation, the methylenetetrahydrofolate reductase (C677T MTHFR) mutation, as well as deficiencies of antithrombin, protein C and protein S is less clear. The methods for diagnosis and the evidence for their associations are discussed in this paper. Treatment modalities independent of those needed to prevent thrombotic events in pregnancy have generally not been studied. Given the present available data, there is insufficient evidence to include inherited thrombophilias in the initial evaluation of RPL. It is important to look for other, more common, causes of recurrent miscarriage in the evaluation of these patients.     

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.     

How strong is the association between maternal thrombophilia and adverse pregnancy outcome? A systematic review.

OBJECTIVE: To determine whether inherited and acquired thrombophilias are associated with adverse obstetric complications. STUDY DESIGN: A systematic review; studies where women with adverse obstetric complications were tested for one or more acquired and inherited thrombophilias were included. MAIN OUTCOME MEASURES: Prevalence of thrombophilia in women with severe pre-eclampsia/eclampsia, severe placental abruption, intrauterine growth restriction or unexplained stillbirth. RESULTS: Compared with controls, placental abruption was more often associated with homozygous and heterozygous factor V Leiden mutation, heterozygous G20210A prothrombin gene mutation, homocysteinaemia, activated protein C resistance or anticardiolipin IgG antibodies. Women with pre-eclampsia/eclampsia were more likely to have heterozygous factor V Leiden mutation, heterozygous G20210A prothrombin gene mutation, homozygous MTHFR C677T mutation, protein C deficiency, protein S deficiency or activated protein C resistance compared with controls. Unexplained stillbirth, when compared with controls, was more often associated with heterozygous factor V Leiden mutation, protein S deficiency, activated protein C resistance, anticardiolipin IgG antibodies or lupus anticoagulant. Women with intrauterine growth restriction had a higher prevalence of heterozygous G20210A prothrombin gene mutation, homozygous MTHFR C677T gene mutation, protein S deficiency or anticardiolipin IgG antibodies than controls. There was wide heterogeneity in the prevalence of thrombophilia between the studies. CONCLUSIONS: Women with adverse pregnancy outcome are more likely to have a positive thrombophilia screen but studies published so far are too small to adequately assess the true size of this association. Screening for thrombophilia should not become standard practice until clear evidence emerges that thromboprophylaxis during pregnancy improves perinatal outcome. Further research into the link between the observed association, causality and heterogeneity is required.     

Thromboembolism and thrombophilia

Thromboembolism remains the major cause of maternal mortality in the UK. There are important differences in the diagnosis and treatment of thrombosis in pregnancy compared with the non-pregnant patient. Thromboprophylaxis for high risk women (for example previous thrombosis) and for women in high risk obstetric situations (for example, Caesarean section) should be considered. Inherited and acquired thrombophilias increase the risk of thrombotic episodes during pregnancy, and may play a role in adverse obstetric events.     

Pregnancy outcomes and the effect of metformin treatment in women with polycystic ovary syndrome: an overview

This article is a review of the literature assessing pregnancy outcomes and the effect of metformin treatment among women with polycystic ovary syndrome (PCOS). A review of research published in English was undertaken using PubMed and MEDLINE databases. The weight of the available evidence suggests that pregnant women with PCOS are at an increased risk of developing gestational diabetes, hypertensive disorders of pregnancy, preterm birth and early pregnancy loss. Obesity is a contributory factor for the increased risk of gestational diabetes in this group of women and is estimated to affect 5-40% of pregnant women with PCOS. The prevalence of other obstetric complications is estimated at 10-30% for gestational hypertension, 8-15% for pre-eclampsia and 6-15% for preterm birth. The association between PCOS and early pregnancy loss may not be direct, wherein the presence of PCOS-associated hyperinsulinemia, leading to hyperandrogenemia, has been implicated in the pathophysiology of early pregnancy loss. Apart from the role of metformin in improving the metabolic consequences accompanying PCOS, it has been shown to improve pregnancy rates in women with PCOS who are resistant to clomiphene citrate. In conclusion, pregnancy in women with PCOS is associated with adverse obstetric outcomes (multiple adverse obstetric risk). Whether metformin should be administered throughout pregnancy still remains controversial. Further prospective studies that foster a larger number of participants and adjust for all potentially confounding factors are needed.     

遗传性易栓症的妊娠期筛查与抗凝治疗评价

汉族人群遗传性易栓症以蛋白C或蛋白S缺乏为主,抗凝血酶缺乏少见,罕见凝血因子ⅤLeiden(FⅤL)突变及PGM突变。遗传性易栓症增加妊娠期血栓栓塞性疾病的风险,是胎盘介导的妊娠并发症的协同性促进因素,而不是主要病因。如果已经明确具有进行治疗的指征,没有必要再行遗传性易栓症的筛查;如果病因不明,而遗传性易栓症筛查的阳性结果可能会影响治疗决策时,筛查或许是有用的。现有证据仅表明,预防性应用低剂量阿司匹林可以减少子痫前期复发。低分子肝素是否能改善胎盘介导的妊娠并发症的再发风险,单中心和多中心研究的结论并不一致。虽然缺乏有力的证据支持,目前仍建议对具有胎盘介导的妊娠并发症病史的遗传性易栓症患者进行选择性、个体化抗凝治疗。     

Acquired and inherited thrombophilia disorders in pregnancy

Thromboembolism is the leading cause of antepartum and postpartum maternal mortality. The presence of antiphospholipid antibodies is responsible for many pregnancy losses and other morbidities in pregnant women, and is the most prevalent and treatable cause of acquired thrombophilia in pregnancy. There is also evidence that women with thrombophilia are at increased risk not only of pregnancy-related venous thromboembolism but other vascular pregnancy complications. Many studies have examined the association between thrombophilia and pregnancy complications. This article reviews the most up-to-date knowledge of prevalence, pathogenesis, and diagnosis of acquired and inherited thrombophilias and their relationship and association with pregnancy complications.     

Inherited thrombophilia and pregnancy with fetal loss

Maternal thrombophilia (inherited and acquired) has recently been identified as a major cause of thrombembolism (TE), but it may also contribute to adverse pregnancy outcomes and recurrent pregnancy loss. If the acquired thrombophilia is a well-established factor in etiology of fetal loss, the contribution of specific inherited thrombophilic genes is still controversial. The most common inherited traits are deficiency of antithrombin, protein C or protein S; Factor V Leiden; prothrombin G20210A; MTHFR C677T This review focuses on association of recurrent fetal loss with specific gene thrombophilic defects. Overall 52% of women with obstetric complication other than TE carry thrombophilic gene defects. The role of specific genes is different in etiology of early and late pregnancy loss. Inherited thrombophilia is now view as multicausal model; clinical manifestation can be heterogeneous result of gene-gene and gene-environment interactions. Therefore the criteria for genetic screening affected women with history of fetal loss should not be very stringent. The implication of screening for thrombophilic mutations allow to find women at risk of thrombosis and vascular gestational abnormalities in which antithrombotic drugs may have potential therapeutic benefit.     

Prothrombin 20210 G-->A, MTHFR C677T mutations in women with venous thromboembolism associated with pregnancy

Over 50 unselected women with maternal venous thromboembolism were screened for the prothrombin 20210 G→A and MTHFR C677T mutations, in addition to screening for other thrombophilias. The prevalence of thrombophilia in these women was compared with its prevalence in the general population in our area. The prothrombin (OR 4.4; 95% CI 1.2-16) and factor V Leiden (OR 4.5; 95% CI 2.1-14.5) mutations were more common in our patients, compared with the general population, whereas women homozygous for the C677T mutation in the methylene tetrahydrofolate reductase gene (OR 0.45; 95% CI 0.13-1.58) were not. It is recommended that women with a personal or strong family history of venous thromboembolism should be screened for the prothrombin mutation either before or early in pregnancy, in addition to screening for other thrombophilias. Screening for the MTHFR mutation does not appear to identify women at increased risk of maternal venous thrombosis.     

High prevalence of the prothrombin gene mutation in women with intrauterine growth retardation, abruptio placentae and second trimester loss

BACKGROUND: It has been reported recently that obstetric complications are associated with thrombophilias. Our objective was to investigate the association between pregnancy complications and the guanine 20210 adenine (G20210A) mutation in prothrombin gene. METHODS: Two hundred and twenty-two women (study group) with obstetric complications were tested for the prothrombin mutation. Indications for testing were: severe preeclampsia, mild preeclampsia, intrauterine growth retardation, severe abruptio placentae, unexplained stillbirth, second trimester loss, and three or more consecutive spontaneous abortions. We also tested 156 healthy women who had at least one normal pregnancy and comprised the control group. RESULTS: Demographic data of the study and control groups were similar. Twenty-eight women of the study group (13%) were found to be heterozygous carriers of the 20210 variant of the prothrombin gene compared to five (3.2%) of the control group, p=0.001, odds ratio (OR) 2.9; 95% confidence interval (CI) 1.3-6.5. Compared to the control women, the prothrombin gene mutation was significantly more prevalent in women with IUGR, abruptio placentae, and second trimester loss but not in women with mild or severe preeclampsia, stillbirth and habitual abortion. CONCLUSIONS: Our data demonstrate that the mutation in the prothrombin gene is associated with specific pregnancy complications.     

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.     

Genetic thrombophilic defects (Factor V Leiden, prothrombin G20210A, MTHFR C677T) in women with recurrent fetal loss

Maternal thrombophilia (inherited and acquired) has recently been identified as a major cause of thrombembolism, but it may also contribute to adverse pregnancy outcomes and recurrent pregnancy loss. To determine the association of specific inherited thrombophilias and recurrent fetal loss (RFL), three gene mutations (Factor V Leiden, prothrombin G20210A, MTHFR C677T) were investigated. The prevalence of the thrombophilic markers was compared in 156 women with history of fetal loss in different trimester of pregnancy and 80 matched controls. At least one thrombophilic defect was found in 28.2% of total study group women compared with 16.2% in controls (p=0.06; OR-2.02) and in 50% of women with RFL in third trimester (p=0.008; OR-5.15). Factor V Leiden was more common in the group of women with fetal loss in third trimester (37.5%) compared to the controls (6.2%) (p=0.002; OR-9.0). Presence of FVL was associated with a significant increased risk for RFL in second and third trimester (OR-6.25; P<0.001) and significant protection for RFL in first trimester (OR-0.16; P<0.001). Mutation prothrombin G20210A or MTHFR C677T was more common in group of women with fetal loss in first trimester compared to the controls (28.3% vs. 11.2% respectively; p=0.009; OR-3.11). The presence of either of these mutations was associated with no significant increased risk for RFL in first trimester (OR-2.5). Genetic thrombophilic defects are common in women with RFL and are associated with late fetal loss. This association is manifest by FVL rather than total number of defects involved.     

Obstetric antiphospholipid syndrome: an update on pathophysiology and management

Antiphospholipid antibodies (aPLs) are acquired antibodies directed against negatively charged phospholipids, a group of inner and outer cell membrane antigens found in mammals. Obstetric antiphospholipid antibody syndrome (APS) is diagnosed in the presence of certain clinical features in conjunction with positive laboratory findings. Although obstetric APS was originally reported in association with slow progressive thrombosis and infarction in the placenta, it is most often associated with a poor obstetric outcome. In fact, obstetric APS is one of the most commonly identified causes of recurrent pregnancy loss (RPL). Thus obstetric APS is distinguished from APS in other organ systems where the most common manifestation is thrombosis. Several pathophysiological mechanisms of action of aPLs have been described. The most common histopathological finding in early pregnancy loss has been defective endovascular decidual trophoblastic invasion. Treatment with heparin and aspirin is emerging as the therapy of choice, with ～75% of treated women with RPL and aPLs having a successful delivery compared with <50% without treatment. This review highlights the diagnostic challenges of obstetric APS, the obstetric complications associated with APS, proposed pathophysiological mechanisms of APS during pregnancy, and the management of women during and after pregnancy.     

Syndrome des ovaires polymicrokystiques : une pathologie à risque obstétrical ?

Polycystic ovary syndrome (PCOS) is the most common endocrine disorder in women of reproductive age and the leading cause of female infertility. This condition is frequently associated with significant metabolic disorders, including obesity and hyperinsulinemia. Therefore, it seems essential to focus on the pregnancy of these patients and possible obstetric complications. Many studies suggest an increase in the risk of obstetric pathology: early miscarriage, gestational hypertension, preeclampsia, gestational diabetes mellitus diagnosed during early pregnancy, prematurity, low birthweight or macrosomia, neonatal complications and cesarean sections. However, it is difficult to conclude clearly about it, because of the heterogeneity of definition of PCOS in different studies. In addition, many confounding factors inherent in PCOS including obesity are not always taken into account and generate a problem of interpretation. However it seems possible to conclude that PCOS does not increase the risk of placental abruption, HELLP syndrome, liver disease, postpartum hemorrhage, late miscarriage and stillbirth.     

Activated protein C resistance and lupus anticoagulant in pregnancy

Thrombophilias, both inherited and acquired, have been reported to be associated with thromboembolic events and severe obstetric complications. This case report examines the case of a patient with two thrombophilias, activated protein C resistance secondary to Factor V Leiden mutation and lupus anticoagulant.     

Activated protein C resistance and lupus anticoagulant in pregnancy

Thrombophilias, both inherited and acquired, have been reported to be associated with thromboembolic events and severe obstetric complications. This case report examines the case of a patient with two thrombophilias, activated protein C resistance secondary to Factor V Leiden mutation and lupus anticoagulant.     

Inheritance and perinatal consequences of inherited thrombophilia in Greece.

OBJECTIVE: To investigate the impact of inherited thrombophilic factors on the gestational outcome of unselected pregnant women. METHOD: A total of 392 women with spontaneous pregnancy were investigated for Factor V Leiden, prothrombin G20210A, and MTHFR C677T mutations. Adverse pregnancy outcomes were recorded. RESULTS: Thrombophilic genotypes were significantly higher in women with placental abruption. Heterozygocity for Factor V Leiden increased the risk for placental abruption 9.1 times. The MTHFR T677T genotype increased the risk for placental abruption 4.8 times despite folate supplements, and normal serum folate and B(12) levels. Women with inherited thrombophilia and previous obstetric complications were at significant risk for complications in a subsequent pregnancy (P<0.05). CONCLUSION: Women with placental abruption should be screened for thrombophilic factors and plasma homocysteine should be measured. Subgroups of women with inherited thrombophilia and obstetric complications might benefit from prophylactic anticoagulation in subsequent pregnancies.