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.     

Increased prevalence of thrombophilia among women with severe ovarian hyperstimulation syndrome

OBJECTIVE: To determine the prevalence of markers of thrombophilia in women hospitalized for severe OHSS. DESIGN: Prospective study. SETTING: Academic research center. PATIENT(S): Women undergoing induction of ovulation complicated by severe OHSS (n = 20) and women undergoing induction of ovulation without development of severe OHSS (n = 41). INTERVENTION(S): Blood samples to test for markers of thrombophilia were obtained during the luteal phase of the treatment cycle. MAIN OUTCOME MEASURE(S): Blood samples were analyzed for markers of thrombophilia, such as plasma levels of antithrombin, protein S and protein C, antiphospholipid antibodies, the factor V Leiden mutation, and 677T polymorphism in the 5,10 methyltetrahydrofolate reductase (MTHFR 677T) gene. RESULT(S): Seventeen of 20 patients with severe OHSS (85%) and 11 of 41 controls (26.8%) had one or more positive markers of thrombophilia. Of the women with severe OHSS, 6 had a decreased antithrombin level, 8 had decreased levels of protein S, 7 were homozygous for the MTHFR 677T mutation, 1 was heterozygous for the factor V Leiden mutation, and 5 had antiphospholipid antibodies. Eight women with OHSS and no controls had more than one positive marker of thrombophilia. CONCLUSION(S): The prevalence of thrombophilia is increased in women with severe OHSS. These findings suggest that prophylactic screening for this disorder and possible use of heparin prophylaxis for thromboembolic phenomena should be considered in these patients.     

Thrombophilia is common in women with idiopathic pregnancy loss and is associated with late pregnancy wastage

OBJECTIVE: To describe the characteristics of thrombophilia in women with idiopathic pregnancy loss. DESIGN: Prospective observational study. SETTING: Tertiary referral center in a teaching academic hospital. PATIENT(S): One hundred forty-five patients with repeated pregnancy loss and 145 matched controls. INTERVENTION(S): Prospective assessment of thrombophilia in patients and controls. MAIN OUTCOME MEASURE(S): Prevalence of activated protein C (APC) resistance, protein C, protein S, and antithrombin III deficiencies, antiphospholipid antibodies, factor V Leiden, factor II G20210A, and MTHFR C677T mutations. RESULT(S): At least one thrombophilic defect was found in 66% of study group patients compared with 28% in control group patients. Combined thrombophilic defects were documented in 21% of women with pregnancy loss compared with 5.5% of control patients. Late pregnancy wastage occurred more frequently in women with thrombophilia compared with women without thrombophilia (160/429 [37%] vs. 39/162 [24%], respectively). APC resistance was documented in 39% of women with pregnancy loss compared with 3% of the control patients. APC resistance without factor V Leiden mutation was documented in 18% of women with pregnancy loss compared with none of the controls. While factor V Leiden mutation was more common in women with pregnancy loss (25% vs. 7.6%), factor II G20210A and homozygosity for MTHFR C677T contributed to pregnancy loss only in the presence of other thrombophilia. CONCLUSION(S): Thrombophilia was found in the majority (66%) of women with idiopathic pregnancy loss. APC resistance with or without factor V Leiden mutation is the most common thrombophilic defect, and combined thrombophilia is a frequent finding in women with pregnancy loss. Thrombophilia is associated with increased frequency of late pregnancy wastage.     

Primary habitual abortions are associated with high frequency of factor V Leiden mutation

OBJECTIVE: To analyze the prevalence of the mutation G1691A in factor V gene (Leiden mutation), of mutation C677T in the methylenetetrahydrofolate reductase (MTHFR) gene, and of polymorphism in G20210A in the prothrombin gene in women with recurrent abortions; further, to identify a subgroup at higher risk of being carriers of these mutations. DESIGN: Prospective case control evaluation. SETTING: University clinic. PATIENT(S): Eighty-four women with 3 or more consecutive miscarriages were compared with 69 controls. INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): Polymerase chain reactions were performed to identify the mutations G1691A in factor V and C677T in MTHFR genes and the polymorphism G20210A in the prothrombin gene. RESULT(S): In women with primary habitual abortions, 27.8% carried the Leiden mutation. No difference was observed in the prevalence of mutation C677T in the MTHFR gene or in polymorphism G20210A in the prothrombin gene. CONCLUSION(S): The Leiden mutation may play a considerable role for women having primary recurrent abortions.     

Prothrombotic gene mutations in women with recurrent abortions and intrauterine fetal death

AIM: The factor V Leiden mutation (FVL) and the G20210 prothrombin gene mutation (FII G20210A) are well-established risk factors for venous thromboembolism. In the recent years many scientific reports have suggested that these defects are associated with an increased risk of intrauterine fetal death. The aim of our study was to investigate the prevalence of these molecular defects in subjects with history of unexplained pregnancy loss. METHODS: One-hundred and fifty women, 99 with history of unexplained recurrent pregnancy loss (between the 13th and the 20th week of gestation) and 51 with history of unexplained fetal death (pregnancy loss after the 20th week of gestation) were studied for hereditary thrombophilia. Physiologic coagulation inhibitors (antithrombin III, protein C, protein S) were in the normal range. RESULTS: The prevalence of FVL and FII G20210A mutations was compared in patients with recurrent pregnancy loss and in a control group of 115 healthy women, without history of pregnancy loss (6.1% and 8.1% for FVL and FII G20210A respectively vs 2.6% for both mutations in the control group, P=0.36 for FVL and P=0.13 for FII G20210A). FVL and FII G20210A mutations were significantly more prevalent in women with fetal death (19.6%, P=0.001 for both mutations). CONCLUSIONS: Our data suggest that the screening for the FVL and FII G20210A mutations is useful in the setting of unexplained early and late pregnancy loss. Further studies are necessary in order to clarify the real impact of prothrombotic molecular defects on the pregnancy outcome and then to evaluate the appropriate therapeutic approach.     

Analyzes of three common thrombophilic gene mutations in German women with recurrent abortions

BACKGROUND: Several etiological factors have been proposed as a cause for recurrent fetal abortions. Changes in blood coagulation during pregnancy may play an important role in the occurrence of recurrent abortions (RA). METHODS: The aim of this study was to investigate the prevalence of factor V Leiden, factor II prothrombin, and methylenetetrahydrofolate reductase (MTHFR) mutations in women with recurrent abortions (> or =2 abortions) in the German population. The mean number of abortions was 3 (range 2-8). RESULTS: Frequencies of the factor V Leiden mutation and the prothrombin G20210A mutation were equally high in the patient group compared with our control group (for factor V Leiden: 11/101 vs. 9/122; p-value: 0.348; for prothrombin G20210A: 2/101 vs. 3/122; p-value: 0.81). Moreover, in both the patient and control groups, 15 of the women were homozygous for the MTHFR C677T allele (15/101 vs. 15/122; p-value: 0.635). The occurrence of FV Leiden, FII and MTHFR mutations was not significantly increased in the patient group compared with our control group. CONCLUSION: The results of the present study reveal no relationship between these common three thrombophilic mutations and recurrent abortions for the German population, and further studies are essentially recommended on whether a thrombophilia evaluation should be performed in patients with recurrent abortions.     

Obstetric aspects of hereditary thrombophilias: epidemiology,complications and prophylaxis

The study gives a survey of literature on obstetric aspects of hereditary thrombophilias e.i. factor V Leiden, prothrombin gene 20210A mutation, antithrombin III deficiency, protein C/protein S deficiency, and hyperhomocysteinemia. All types of thrombophilia cause similar pathomorphological changes in placenta and decidua (high number of infarcts and microclots, decidual vasculopathia) as well as insufficient invasion of cytotrophoblast in spiral arteries. The study also discusses prophylactic rules: application of low molecular weight heparin and non-fractionated heparin in prophylaxis and in hyperhomocysteinemia application of folic acid.     

遗传性易栓症与不良妊娠结局的研究进展

近年研究发现妊娠期易栓症的发生呈增加趋势。易栓症分为遗传性易栓症和获得性易栓症,遗传性易栓症主要与凝血基因突变所致的蛋白表达异常有关,包括因子VLeiden(FVL)、凝血酶原基因G20210A、亚甲基四氢叶酸还原酶(MTHFR)基因突变以及蛋白S(PS)、蛋白C(PC)和抗凝血酶(AT)缺乏等。凝血、抗凝及纤溶系统功能失调可引起胎盘灌注不良,不良妊娠结局如子痫前期(PE)、胎盘早剥、胎儿生长受限(FGR)和习惯性流产等可能与此有关。但遗传性易栓症是否是造成不良妊娠结局的直接因素以及预防性抗凝是否可以改善妊娠结局仍需进一步探讨。综述遗传性易栓症与不良妊娠结局的关系,评估预防性抗凝的必要性,为临床诊断和治疗提供思路。     

Single inherited thrombophilias and adverse pregnancy outcomes

INTRODUCTION: Inherited thrombophilia is believed to be a multiple gene disease with more than one defect. We aimed to determine the association between single thrombophilic patterns and a variety of pregnancy diseases. METHODS: 284 pregnant women were recruited for the present study and were divided in two groups: A group (176 controls) and B group (108 cases). Patients belonging to the B group had one of the following: severe pre-eclampsia, hemolysis, hepatic enzymes increase, hypertension and low platelet count (HELLP) syndrome, gestational hypertension, fetal growth restriction, intrauterine death, abruptio placentae and disseminated intravascular coagulopathy. To detect methylenetetrahydrofolate reductase (MTHFR) A1298C, MTHFR C677T, factor V Leiden, PAI-1, mutant prothrombin G20210A, an inverse hybridization technology was used. Plasma homocysteine, antithrombin (AT) III and protein S were determined. A modified functional activated protein C resistance was detected. RESULTS: MTHFR C677T and hyperhomocysteinemia were more prevalent than other thrombophilias. Deficiency in AT III was significantly linked with pre-eclampsia (relative risk 0.88; 95% CI 0.83-0.94). Activated protein C resistance (APCR) was significantly related to the abruptio placentae (relative risk 0.71; 95% CI 0.61-0.82). COMMENTS: Apart from the linkage between AT III deficiency and the occurrence of pre-eclampsia, and apart from the increased risk of abruptio placentae in pregnant women with altered APCR, we obtained findings in contrast with some of the published literature. In our case series, no association of pre-eclampsia with factor V Leiden or with prothrombin gene mutation was found.     

Pathologic features of the placenta in women with severe pregnancy complications and thrombophilia.

OBJECTIVE: To compare placental pathology between women with and without thrombophilia who had severe preeclampsia, intrauterine growth retardation, severe abruptio placentae, or stillbirth. METHODS: After delivery, 68 women with singleton pregnancies with one of the above complications were evaluated for an inherited thrombophilia: factor V Leiden, methylenetetrahydrofolate reductase and prothrombin gene mutation, and deficiencies of protein S, protein C, and antithrombin III. Thirty-two women were thrombophilic (group A), and 36 women were not (group B). There was no difference in maternal age, parity, and type of pregnancy complication. A single pathologist examined each placenta. RESULTS: The gestational age at delivery, birth weight, and placental weight were significantly lower in group A. Three parameters showed significant differences between the groups: thrombophilic women had a higher number of villous infarcts (P <.01), more multiple infarcts (P <.05), and a higher incidence of placentas with fibrinoid necrosis of decidual vessels (P <.05). CONCLUSION: Placentas of women with severe complications and thrombophilia have an increased rate of vascular lesions.     

Testing for inherited thrombophilia in recurrent miscarriage

Approximately 1-5% of women trying to conceive experience recurrent miscarriage, and in 50% of these women, the cause of the preceding miscarriages is unknown. Inherited thrombophilias such as factor V Leiden mutation, prothrombin gene mutation (PT 20210A), and deficiencies of natural anticoagulants protein C, protein S, and antithrombin are associated with recurrent miscarriage. Knowledge of the association between inherited thrombophilia and recurrent miscarriage and of potential treatment options for improving chances of a live birth could tempt physicians to test for inherited thrombophilia in women with recurrent miscarriage. However, the strength of the association between inherited thrombophilia and recurrent miscarriage is not very strong, and more importantly, no evidence indicates that the use of anticoagulants improves the chance of live birth in these women. With the current state of evidence, testing for inherited thrombophilia should not lead to altered clinical management and therefore, should not be performed routinely in women with recurrent miscarriage but only in the context of scientific studies.     

Severe preeclampsia and high frequency of genetic thrombophilic mutations

OBJECTIVE: To determine whether severe preeclampsia is associated with genetic thrombophilic mutations or other types of thrombophilia. METHODS: A case-control study compared 63 consecutive women with severe preeclampsia evaluated at our institution between November 1997 and April 1999 with 126 control women matched for age and ethnicity. All of these women were tested several months after delivery for mutations of factor V Leiden, methylenetetrahydrofolate reductase, and prothrombin gene; for deficiencies of protein C, protein S, and antithrombin-III; and for the presence of anticardiolipin antibodies. RESULTS: Thirty-five study women (56%) had a thrombophilic mutation compared with 24 control women (19%), P <.001. Seven other study women (11%) had other thrombophilias, compared with one control woman (0.8%), P <.01. Within the study group, women with thrombophilia delivered at an earlier gestational age, and their neonates' birth weights were lower compared with those of women without thrombophilia. CONCLUSION: Because thrombophilia was found in 67% of women with severe preeclampsia, we suggest that women who have severe preeclampsia should be tested for thrombophilia.     

Thrombophilic mutations in pre-eclampsia and pregnancy-induced hypertension

AIM: The aim of the present study was to determine the existence or prevalence of thrombophilic markers such as Factor V Leiden, prothrombin G20210A, protein S, protein C, activated protein C and anti-thrombin in pre-eclampsia and pregnancy-induced hypertensive patients. METHODS: Blood samples were collected from a total number of 124 women at the maternity unit, University of Malaya Medical Center. These included 49 patients with pre-eclampsia, 63 patients with pregnancy-induced hypertension and 12 normal pregnant women. DNA was extracted from the blood samples. Factor V Leiden (Taq I) and prothrombin G20210A (Hind III) genotyping was done on polymerase chain reaction-restriction fragment length polymorphism. Anti-thrombin activity and the concentrations of protein C, protein S and activated protein C were measured using the IL Coagulation System (Hemosil). RESULTS: Of the 124 subjects, one pre-eclampsia patient was homozygous for Factor V Leiden mutation but prothrombin G20210A mutation was not present in any of the subjects. The subject with Factor V Leiden mutation also had a low activated protein C resistance and a low protein S concentration. CONCLUSIONS: Factor V Leiden mutation is present in the Asian population and may very well serve as one of the genetic factors responsible for pre-eclampsia and other adverse pregnancy outcomes.     

HELLP syndrome and factor V Leiden

The association of thrombophilia and obstetrical complications is documented and well consistent with the hypothesis of an insufficient placental perfusion due to fibrin deposition as a major underlying pathophysiological mechanism. Factor V Leiden is one of the most frequent thrombophilic mutations. A high prevalence of this mutation has recently been reported in a group of 21 German women with haemolysis, elevated liver enzymes, low platelets (HELLP) syndrome. In this respect, we studied the prevalence of factor V Leiden in 18 women who were consecutively diagnosed at our Department of Obstetrics and Gynaecology as having HELLP syndrome, between 1995 and 1999.Women were tested either at the time of diagnosis or months or years after delivery for coagulation parameters, protein C (PC), protein S (PS), antithrombin III, lupus-like anticoagulant, anticardiolipin antibodies (ACA), activated protein C (APC) resistance and detection of the G1691A mutation (factor V Leiden). In all women, the parameters studied were normal and in none of the investigated cases was the G1691A mutation found. HELLP being a severe form of preeclampsia, we think that the reported association between factor V Leiden and HELLP may reflect the well-known association with preeclampsia.     

Risk of thrombophilia in carriers of thrombophilic genetic factors in unsuccessful assisted reproduction

The aim of this study was to evaluate an association of carrier status of common inherited thrombophilic genetic mutations and implantation failure after assisted reproduction (ART): IVF and ICSI. Sixty seven women with failure of embryo implantation and ninety six controls--women without obstetric complication were investigated for carriage of factor V Leiden (FVL), G20210A prothrombin gene mutation, genetic variant C677T in methylentetrahydrofolate reductase gene (MTHFR) and polymorphism A2 in platelet glycoprotein IIb/IIIa (GIPr IIb/IIIa). A significantly higher prevalence of polymorphism A2 in GIPr IIb/IIIa was found in women with implantation failure in ART compared to controls (respectively 26.1% and 12.5%; OR: 2.571, 95% CI: 1.066-6.258, p = 0.033). A higher but not significant prevalence of G20210A prothrombin gene mutation carriage was found inpatients compared to controls (respectively 5.8% and 3.13%, OR: 1.968, 95% CI 0.356-11.539). The carriage of FVL was a little but not significantly higher in controls. The carriage of genetic variant C677T in MTHFR was the same in both groups. These data suggest that polymorphism A2 in GIPr IIb/IIIa and G20210A prothrombin gene mutation could be play a role in the etiology of IVF failures and the carriers of GIPr IIb/IIIa A1/A2 and G20210A prothrombin gene mutation are at higher risk of implantation failure and not successful ART outcome. The carriage of these two genetic defects should be investigated in women undergoing IVF and the antithrombotic or anticoagulant prophylaxis should be indicated for carriers of these two factors.     

Factor V Leiden and prothrombin 20210 G-A mutations in controls and in patients with thromboembolic events during pregnancy or the puerperium

Factor V Leiden and prothrombin 20210 G-A mutations are independent risk factors for venous thrombosis. We studied the frequency of these mutations in 35 patients who had thromboembolic events during pregnancy and puerperium, and in 32 women who had a history of uncomplicated pregnancy, delivered either vaginally or by cesarean section, and did not have a past history of thromboembolism. Factor V Leiden mutation was present in 7 patients (20%) in the study group. Of these 7 patients, 1 was homozygote, whereas the remaining 6 were heterozygote for the mutation. Prothrombin 20210 G-A mutation was present in 2 patients (5.7%) in the study group. In the control group none of the 32 patients was positive for the factor V Leiden and prothrombin 20210 G-A mutations. Our findings indicate that the factor V Leiden mutation is an important risk factor for thromboembolic disease during pregnancy or puerperium.     

Third trimester nonrecurrent fetal loss is associated with factor V Leiden and prothrombin gene mutations.

OBJECTIVE: To determine the role of factor V Leiden and prothrombin gene mutation in the pathogenesis of unexplained second and third trimester nonrecurrent fetal loss. MATERIALS AND METHODS: One hundred and fourteen women with unexplained nonrecurrent late fetal loss made up the study group, and 106 normal pregnant women with a history of delivery of at least one healthy fetus and no history of late fetal loss made up the control group. The study group was further divided into two subgroups: second (n = 36) and third (n = 78) trimester fetal loss. All women were tested for factor V Leiden and G20210A prothrombin gene mutations. RESULTS: Twenty-one (18.4%) of the women in the study group and seven (6.6%) of the women in the control group were heterozygous carriers of factor V Leiden mutation (OR = 3.19). Eleven (9.6%) of the women in the study group and three (2.8%) of the women in the control group were heterozygous carriers of prothrombin gene mutation (OR = 3.66). In assessing with regard to trimesters, 18 (23%) factor V Leiden and 10 (12.8%) prothrombin gene mutations were present in the group of third trimester fetal loss (OR = 4.24 and OR = 5.04, respectively). Three (8.3%) factor V Leiden and one (2.7%) prothrombin gene mutation were detected in women with second trimester fetal loss (OR = 1.28 and OR = 0.40, respectively). CONCLUSION: Factor V Leiden and prothrombin gene mutations were associated with third trimester nonrecurrent fetal loss. These mutations should be screened in women with third trimester but not second trimester unexplained nonrecurrent late fetal loss.     

Preconception counseling for women with thrombophilia

Inherited thrombophilias are a heterogeneous group of coagulation disorders that predispose individuals to thromboembolic events. This group of conditions is the major risk factor for thromboembolism during pregnancy and the puerperium. In addition, thrombophilias have been associated with several adverse obstetric events, including pregnancy loss, preeclampsia, placental abruption, and intrauterine growth restriction. An increased risk for these obstetric complications has prompted many authorities to recommend screening and treating pregnant women for thrombophilias. Optimal obstetric management, however, is controversial as thrombophilias are common and many affected individuals are asymptomatic. Indeed, pregnancy outcome in most women with thrombophilias is normal. The most commonly identified inherited thrombophilias are the factor V Leiden and prothrombin G20210A gene mutations. More rare thrombophilias include protein C and S deficiencies, antithrombin III deficiency. Although relatively common, the association between hyperhomocysteinemia and associated mutations (such as the C677 T methylenetetrahydro-folate reductase) and obstetric complications is controversial.     

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.