Outcome of the subsequent pregnancy after a first loss in women with the factor V Leiden or prothrombin 20210A mutations

Impact of a previous late miscarriage on subsequent pregnancy outcomes: A retrospective cohort study over 10 years

OBJECTIVE

To explore the prognostic impact of a previous late miscarriage (LM) on the subsequent pregnancy outcomes of women with infertility.

METHOD

This retrospective cohort study included couples who had experienced LM following their first embryo transfer during an in vitro fertilization (IVF) cycle from January 2008 to December 2020. Subgroup analysis and binary logistic regression were performed to evaluate the associations between LM due to different causes and subsequent pregnancy outcomes.

RESULTS

A total of 1072 women who had experienced LM were included in this study, comprising 458, 146, 412, and 56 women with LM due to unexplained factors (unLM), fetal factors (feLM), cervical factors (ceLM; i.e. cervical incompetence), and trauma factors (trLM), respectively. Compared with the general IVF (gIVF) population, the early miscarriage rate was significantly higher in the unLM group (8.28% vs. 13.47%, adjusted odds ratio [OR] 1.60, 95% confidence interval [95% CI] 1.12-2.28; P = 0.01). Furthermore, women in the unLM and ceLM groups had a dramatically increased risk of recurrent LM (unLM: 4.24% vs. 9.43%, aOR 1.91, 95% CI 1.24-2.94; P = 0.003; ceLM: 4.24% vs.15.53%, aOR 2.68, 95% CI 1.82-3.95; P < 0.001) and consequently a reduced frequency of live birth (unLM: 49.96% vs. 43.01%, aOR 0.75, 95% CI 0.61-0.91; P = 0.004; ceLM: 49.96% vs. 38.59%, aOR 0.61, 95% CI 0.49-0.77; P < 0.001) compared with the gIVF population.

CONCLUSION

A previous LM due to an unexplained factor or cervical incompetence was significantly associated with a higher risk of miscarriage and a lower live birth rate after subsequent embryo transfer.

New studies of low-molecular-weight heparin in pregnancy

Several aspects of the diagnostic and therapeutic management of women with venous thrombosis are uncertain, because of the absence of adequately sized observational or intervention studies. Here, I will discuss the rationale and design of two currently ongoing investigator-initiated, international, randomized controlled trials of LMWHin pregnancy. The Highlow study (www.highlowstudy.org; NCT Clinicaltrials.gov) 01828697) investigates two doses of low-molecular-weight heparin to prevent recurrent venous thromboembolism (VTE) in pregnant women with a history of VTE. The ALIFE2 study (www.alife2study.org; www.trialregister.nl, NTR 3361) investigates the effect of LMWH on live birth in women with inherited thrombophilia and two or more miscarriages.

Maternal thrombophilia and adverse pregnancy outcome: a case-control study

OBJECTIVE

To assess the risk of adverse pregnancy outcomes in patients with acquired and/or congenital thrombophilia factors.

PATIENTS AND METHODS

A cohort of 130 women with a history of pregnancy loss and no successful gestation were investigated for the presence of congenital and acquired thrombophilia factors, and then compared with a control group of 130 healthy women who had had at least one successful gestation and no pregnancy loss, and were screened for congenital and acquired thrombophilia factors.

RESULTS

Acquired and congenital thrombophilia factors were found in 30 (23%) patients and in 14 (10.8%) controls (p < 0.015). The presence of ≥1 congenital thrombophilia factor was associated with pregnancy loss with an odds ratio of 2.46 (p = 0.040). Moreover, women who had had >1 early fetal loss had a 2.85-fold risk of being carriers of congenital thrombophilia factors, compared to the controls.

CONCLUSION

Our study showed the increased risk of miscarriage in patients with congenital thrombophilia factors and >1 early fetal loss.

Comparative incidence of pregnancy outcomes in thrombophilia-positive women from the NOH-APS observational study

Fetal death is more frequent in women with prior abortions carrying F5 rs6025 or F2 rs1799963 polymorphisms vs nonthrombophilic women. Pregnancy complications are less frequent in LMWH-treated thrombophilic women with fetal loss vs untreated nonthrombophilic women.

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.

Preventing thrombophilia-related complications of pregnancy: an update

Approximately half of all pregnancy-related venous thromboembolic events are associated with thrombophilia. Although the most compelling data for a link between thrombophilia and other adverse pregnancy outcomes derive from women with antiphospholipid antibodies, some studies also suggest an association between these pregnancy complications and hereditary thrombophilias. Management of thrombophilia often involves anticoagulant therapy; however, use of these agents during pregnancy is challenging. There is a paucity of high-quality studies and consequently, recommendations are based largely on extrapolation from data in nonpregnant women, in addition to observational studies and a few small randomized studies. This article will review the impact of the thrombophilias on pregnancy and its outcome, evidence for therapies aimed at the prevention of thrombophilia-related pregnancy complications, and the most recent recommendations contained in the 9th Edition of the American College of Chest Physicians Evidence-Based Clinical Practice Guidelines.

Inherited and acquired thrombophilias

Thrombophilias represent an evolving story that continues to stir controversy for care providers and obstetrical patients. The predominant thrombophilic mutations include the factor V Leiden mutation, prothrombin gene mutation G20210A, methylene tetrahydrafolate reductase C667T, and deficiencies of the natural anticoagulants proteins C and S, and antithrombin. Prospective cohort studies have provided an accurate assessment of the risk of placenta-mediated complications posed by common inherited thrombophilic conditions. Acquired thrombophilic conditions consist of the antiphospholipid antibody syndrome (APAS) and hyperhomocysteinemia. Well-conducted, placebo-controlled, randomized trials have demonstrated no benefit of anticoagulation in women with recurrent pregnancy loss and inherited thrombophilia. The routine use of anticoagulation to prevent other placenta-mediated complications in the setting of inherited thrombophilia should be considered experimental until the results of adequate clinical trials are available. Heparin anticoagulation and antiplatelet therapies are the cornerstone of treatment of APAS in pregnancy.

Antithrombotic therapy for pregnancy loss

BACKGROUND Although an association between thrombophilia and pregnancy loss has been observed in many studies, little is known about the pathophysiological mechanisms behind this association. Considering the association between thrombophilia and pregnancy loss, the efficacy of antithrombotic therapy for women with pregnancy loss (with or without thrombophilia) has been studied for the past 30 years. METHODS We performed a comprehensive review of the literature on the strength of the association between thrombophilia and pregnancy loss, the pathophysiological mechanisms and the efficacy of antithrombotic therapy to increase the chance of live birth. RESULTS The association between pregnancy loss and thrombophilia varies according to the type of thrombophilia (e.g. antiphospholipid syndrome versus forms of inherited thrombophilia) and according to the type of pregnancy loss (single versus recurrent pregnancy loss and early versus late pregnancy loss). Thrombophilia may induce thrombosis in decidual vessels or impair placentation through hypercoagulability and inflammation, but these hypotheses need further verification. For women with antiphospholipid syndrome, evidence from small-sized trials suggests a beneficial effect of antithrombotic therapy but additional randomized controlled trials are essential to confirm this. Whether antithrombotic therapy increases the chance of live birth in women with inherited thrombophilia is unknown. Recent randomized controlled trials have consistently shown that antithrombotic therapy does not increase the chance of live birth in women with unexplained recurrent miscarriage. CONCLUSIONS There are large gaps in knowledge and a lack of evidence for treatment of women with pregnancy loss with thrombophilia. To provide a solid base for clinical practice, further studies on the role of coagulation in reproduction, as well as international collaborations in randomized controlled trials of antithrombotic therapy in women with pregnancy loss, and antiphospholipid syndrome or inherited thrombophilia are urgently needed.

Thrombosis in women: what are the knowledge gaps in 2013?

Several aspects of the diagnostic and therapeutic management of women with venous thrombosis are uncertain. In this overview, I will discuss three major areas. First, the contribution of hormone use to venous thromboembolism (VTE) will be discussed as prudent prescribing of safe preparations can further reduce the risk of hormone-related VTE. Uncertainties remain regarding certain low-dose progestagens and transdermal routing of hormones and their associated risk of VTE. Second, I will review the diagnosis, treatment, and prevention of pregnancy-related VTE. As direct evidence is largely absent for these individuals, these areas are subject to extrapolation from the non-pregnant population. There is therefore an urgent need for the evaluation of diagnostic strategies that safely exclude the diagnosis of acute pulmonary embolism in pregnant women without the need for diagnostic imaging, which is currently the gold standard, as no studies have confidently demonstrated the safety of ruling out VTE by clinical probability assessment combined with the use of D-dimer levels. Although identification of women at increased risk of pregnancy-related VTE is relatively well established, controversy remains for asymptomatic women from thrombophilic families. The optimal duration and intensity of anticoagulant treatment for, and prophylaxis of, pregnancy-related VTE with low molecular weight heparin is unknown. Third, anticoagulant therapy to prevent recurrence in women with unexplained recurrent miscarriage has shown to have no benefit and should not be prescribed. However, whether antithrombotic therapy prevents recurrent miscarriage in thrombophilic women, or in women with severe pregnancy complications, remains unknown and urgently requires future research.

Risk of placenta-mediated pregnancy complications or pregnancy-related VTE in VTE-asymptomatic families of probands with VTE and heterozygosity for factor V Leiden or G20210 prothrombin mutation

BACKGROUND

Few studies have evaluated the risk of pregnancy-related adverse events in asymptomatic relatives of probands for VTE and factor V Leiden or the G20210A variant. The antepartum management of this population ranges from antepartum anticoagulation therapy to clinical surveillance.

OBJECTIVE

To evaluate the risk of placenta-mediated pregnancy complications and pregnancy-related VTE in VTE-asymptomatic families of probands with VTE and who are heterozygous carriers of either factor V Leiden or PT-G20210A mutation.

METHODS

One hundred and fifty-eight relatives, who had 415 pregnancies, were retrospectively evaluated. Odds ratios and 95% confidence intervals were calculated to compare pregnancy outcomes between women with and without thrombophilia.

RESULTS

In the factor V Leiden group, 22 placenta-mediated pregnancy events of 152 pregnancies (14.4%) were reported, compared with 25 adverse events of 172 pregnancies in the G20210A prothrombin group (14.5%) and 13 adverse events of 91 pregnancies in the non-carrier group (14.2%). Carriers of factor V Leiden or G20210A prothrombin were not associated with a higher risk of pregnancy-adverse outcomes compared with non-carriers: OR 1.02 (95% CI, 0.40-2.25) and 1.25 (95% CI, 0.48-3.24), respectively. Four episodes of pregnancy-associated VTE of 415 pregnancies (0.96%) were recorded. Two episodes of VTE in the G20210A group, one in the factor V Leiden group, and one episode in the non-carrier group were noted.

CONCLUSIONS

In VTE-asymptomatic relatives of probands with VTE, the presence of factor V Leiden or the G20210A prothrombin mutation in heterozygosis should not lead to a decision to instigate antepartum prophylaxis.

Comparison of uterine artery Doppler in pregnant women with thrombophilia treated by LMWHs and without thrombophilia

OBJECTIVE

The aim of this study was to use uterine artery Doppler ultrasonography to investigate the cases of women with thrombophilia who used LMWH during the 18-22-week period of gestation.

METHODS

This retrospective study was conducted at our university between January 2005 and July 2010. 64 patients were treated with low-dose LMWHs (enoxaparine 40 mg) from the beginning of pregnancy until 36 weeks of gestation. Fifty control subjects were also included in this study. Transabdominal ultrasound examination and bilateral uterine artery Doppler measurements pulsatility index (PI), resistive index (RI), and systole/diastole measurement (S/D) were performed during the 18-22-weeks period of gestation.

RESULTS

No significant differences were found between the groups with respect to maternal age or gestational age at the time of uterine artery Doppler. However, the mean PI (1.07 ± 0.46 for LMWH group and 0.91 ± 0.31 for control, p = 0.036) and the mean RI (0.59 ± 0.12 for LMWH group and 0.54 ± 0.10 for control, p = 0.021) were significantly higher in the trombophilia group.

CONCLUSION

Women with trombophilia still have an increased mean PI and RI, as determined by uterine artery Doppler ultrasonography during the 18-22-week period of gestation, even if they use LMWH.

VTE, thrombophilia, antithrombotic therapy, and pregnancy: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines

BACKGROUND

The use of anticoagulant therapy during pregnancy is challenging because of the potential for both fetal and maternal complications. This guideline focuses on the management of VTE and thrombophilia as well as the use of antithrombotic agents during pregnancy.

METHODS

The methods of this guideline follow the Methodology for the Development of Antithrombotic Therapy and Prevention of Thrombosis Guidelines: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines in this supplement.

RESULTS

We recommend low-molecular-weight heparin for the prevention and treatment of VTE in pregnant women instead of unfractionated heparin (Grade 1B). For pregnant women with acute VTE, we suggest that anticoagulants be continued for at least 6 weeks postpartum (for a minimum duration of therapy of 3 months) compared with shorter durations of treatment (Grade 2C). For women who fulfill the laboratory criteria for antiphospholipid antibody (APLA) syndrome and meet the clinical APLA criteria based on a history of three or more pregnancy losses, we recommend antepartum administration of prophylactic or intermediate-dose unfractionated heparin or prophylactic low-molecular-weight heparin combined with low-dose aspirin (75-100 mg/d) over no treatment (Grade 1B). For women with inherited thrombophilia and a history of pregnancy complications, we suggest not to use antithrombotic prophylaxis (Grade 2C). For women with two or more miscarriages but without APLA or thrombophilia, we recommend against antithrombotic prophylaxis (Grade 1B).

CONCLUSIONS

Most recommendations in this guideline are based on observational studies and extrapolation from other populations. There is an urgent need for appropriately designed studies in this population.

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.

Can Factor V Leiden and prothrombin G20210A testing in women with recurrent pregnancy loss result in improved pregnancy outcomes?: Results from a targeted evidence-based review

Women with recurrent pregnancy loss are offered Factor V Leiden (F5) and/or prothrombin G20210A (F2) testing to identify candidates for anticoagulation to improve outcomes. A systematic literature review was performed to estimate test performance, effect sizes, and treatment effectiveness. Electronic searches were performed through April 2011, with review of references from included articles. English-language studies addressed analytic validity, clinical validity, and/or clinical utility and satisfied predefined inclusion criteria. Adequate evidence showed high analytic sensitivity and specificity for F5 and F2 testing. Evidence for clinical validity was adequate. The summary odds ratio for association of recurrent pregnancy loss with F5 in case-controlled studies was 2.02 (95% confidence interval, 1.60-2.55), with moderate heterogeneity and suggestion of publication bias. Longitudinal studies in women with recurrent pregnancy loss or unselected cohorts showed F5 carriers were more likely to have a subsequent loss than noncarriers (odds ratios: 1.93 and 2.03, respectively). Results for F2 testing were similar. For clinical utility, evidence was adequate that anticoagulation treatments were ineffective (except in antiphospholipid antibody syndrome) and had treatment-associated harms. The certainty of evidence is moderate (high, moderate, and low) that anticoagulation of women with recurrent pregnancy loss and F5/F2 variants would currently lead to net harms.

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.

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.

Thromboprophylaxis and pregnancy outcomes in asymptomatic women with inherited thrombophilias

OBJECTIVE

Our objective was to evaluate the effect of thromboprophylaxis on pregnancy outcomes in asymptomatic women with inherited thrombophilias.

STUDY DESIGN

This was a retrospective cohort study of asymptomatic pregnant women with inherited thrombophilias. Medical records were reviewed for pregnancy events, diagnosis of thrombophilias, and management in subsequent pregnancies. Outcomes in women who were and were not treated with thromboprophylaxis were compared using Fisher's exact test and logistic regression.

RESULTS

Fifty-three women had 75 pregnancies subsequent to their diagnosis of thrombophilia. Women treated with heparin had similar rates of live births (86% vs 82%; P = .8, Fisher's exact test) as those not treated. The odds ratio of live birth in all pregnancies for women treated with heparin was compared with untreated women and was 1.9 (95% confidence interval, 0.5-6.3).

CONCLUSION

Pregnancy outcomes are often good in asymptomatic women with thrombophilias in the absence of treatment. Treatment of these women during pregnancy should be considered investigational.

Inherited thrombophilias and unexplained pregnancy loss: an incident case-control study

BACKGROUND

Despite an initial impressive impact, a critical appraisal of the link between pregnancy loss and inherited thrombophilias is currently growing. Furthermore, little is known about the paternal thrombophilic phenotype and pregnancy loss.

OBJECTIVE

We sought an association between unexplained pregnancy loss and parental factor V Leiden (FVL) and Prothrombin G20210A (PTG) mutations.

METHODS

Design - Incident case-control study. Setting- University Hospital of Brest (France). Patients - Women and their partners from the West Brittany area, consecutively referred for unexplained pregnancy losses (two or more consecutive losses at or before 21 weeks of gestation, or at least one later loss). Controls - Women and their partners with no history of pregnancy loss and at least one normal pregnancy, from the same geographic area, recruited using electoral lists. Statistical analysis - Comparison of FVL and PTG allele frequency between cases and controls using the chi-square test. Separate analyses were performed according to the type of pregnancy loss (early recurrent or later loss).

RESULTS

311 women (mean age: 32.8) and 284 of their partners were enrolled as cases while 599 women (mean age: 34.3) and 297 of their partners were recruited as controls. The prevalence of female, male or couple thrombophilic mutations was not statistically different between cases and controls whatever the definition of pregnancy loss retained.

CONCLUSIONS

Presently, there is no clinical indication to routinely test for FVL and likely PTG mutations in women with early recurrent pregnancy loss. Moreover, our results did not reveal that paternal thrombophilic polymorphism should be further explored.

The G20210A prothrombin variant and the risk of venous thromboembolism or fetal loss in pregnant women: a family study

BACKGROUND

The relationship between the G20210A prothrombin variant (PT-G20210A) and adverse pregnancy outcome has been studied by several groups in the last few years. However, because of the different design and sample sizes of these studies the estimated risks have varied.

OBJECTIVE

In this retrospective, multi-center, cohort study we assessed the risk of thromboembolic or obstetric complications in women belonging to families of probands with isolated PT-G20210A and that were symptomatic for venous thromboembolism (VTE).

METHODS

Two hundred and eighty-three female family members that had been pregnant at least once were enrolled. The occurrence of VTE and obstetric complications during pregnancy and postpartum were assessed in carriers of PT-G20210A and compared with non- carriers.

RESULTS

One thromboembolic event occurred during the postpartum period in the carriers group. In the same group, 48 out of 359 pregnancies resulted in unexplained fetal loss as compared with 50 out of 357 pregnancies in the non-carriers (RR 0.9; 95% CI: 0.7-1.4). After adjustment, carriers of PT-G20210A showed a trend towards a higher risk of late fetal loss as compared with non-carriers (RR 2.2; 95% CI: 0.8-6.2). Furthermore, in pregnancies subsequent to those with previous fetal loss there was not a different risk of adverse outcome regardless of the carrier status.

CONCLUSIONS

Female family members who are heterozygous carriers of isolated PT-G20210A do not seem to be at significant increased risk for fetal loss as compared with non-carriers. Screening for PT-G20210A of fertile age women belonging to these families is not warranted in this situation.