A systematic review of the association between factor V Leiden or prothrombin gene variant and intrauterine growth restriction

Postpartum maternal thrombophilia workup value in pregnancies with severe small for gestational age

INTRODUCTION

In the absence of prenatal etiology explaining small for gestational age (SGA), a blood workup may be performed postpartum to look for maternal thrombophilia if a newborn is confirmed to be growth-restricted at birth. The literature regarding thrombophilia factors and fetal growth restriction is discordant. The main objective was to assess the prevalence and type of maternal thrombophilia among women delivering newborns of birthweight below the 3rd percentile and undergoing a postpartum thrombophilia workup and placental analysis.

MATERIAL AND METHODS

This was a single-center retrospective observational cohort study in a tertiary care French maternity. The study population included all women delivering a liveborn infant with severe SGA, defined as a birthweight below the 3rd percentile according to French charts between January 2014 and December 2018. Data from thrombophilia workups (antiphospholipid antibodies, protein C assay, protein S assay, antithrombin assay, factor V Leiden mutation, and factor II G 20210A mutation search) were collected from medical records. Placental pathology analysis, if available, was also collected. The primary endpoint was the prevalence of positive expanded thrombophilia workup (inherited or acquired).

RESULTS

A total of 733 patients were included in our study, 401 of whom (54.7%) underwent a postpartum thrombophilia workup. The overall prevalence of hereditary thrombophilia was 6.7%, 95% confidence interval (4.3 to 9.2) and of acquired thrombophilia was 2.0%, 95% confidence interval (0.6 to 3.4). Among hereditary anomalies, heterozygous factor V mutation and heterozygous factor II mutation were the most frequently observed, respectively, 4% and 1.7%. Concerning the presence of antiphospholipid antibodies, triple positivity was present in one patient (0.2%). The presence of a single antiphospholipid antibody was more frequently observed in 3 patients (0.7%).

CONCLUSIONS

Among patients with a severe SGA infant and postpartum investigation of maternal thrombophilia, an extensive workup of postpartum thrombophilia contributed to a low proportion of positive findings. This suggests that the prescription of such a workup should be targeted, based on personal and family medical history. In fact, testing for inherited thrombophilia should be reserved for patients with a personal or family history of thrombosis. Testing for antiphospholipid antibodies should follow ACR/EULAR criteria.

Impact of Inherited Thrombophilia in Women with Obstetric Antiphospholipid Syndrome: A Single-Center Study and Literature Review

Inherited thrombophilia (IT) has been implicated as a potential causal factor of adverse pregnancy outcomes (APOs), including recurrent miscarriage with and without the presence of antiphospholipid syndrome (APS). The aim of this study was to assess the prevalence and impact of IT on fetal-maternal outcomes and thrombotic risk in women within the spectrum of obstetric APS. Three hundred and twenty-eight women with APS-related obstetric morbidity ever pregnant were included. Of these, 74 met the APS classification criteria, 169 were non-criteria (NC)-APS, and 85 were seronegative (SN)-APS. Patients with other autoimmune diseases were excluded. APOs included early pregnancy loss, fetal death, preeclampsia, abruptio placentae, and preterm birth. Successful pregnancy was defined as the achievement of a live newborn. A literature search was also performed. The mean age of the overall group was 33.9 ± 5.3 years, and the patients were followed up for 35 (11-79) months. During the study period, there were 1332 pregnancies. Nearly 14% of the patients had an associated IT. IT patients more frequently received the standard-of-care (SoC) therapy. The presence of IT was not associated with worse maternal-fetal outcomes in patients treated with SoC treatment. Overall, IT patients had a lower frequency of newborns without treatment, especially those without definite APS. In addition, IT did not increase the risk of thrombosis during pregnancy or the postpartum period. A detailed analysis of the literature review identified only four publications related to our study and did not show conclusive evidence of the impact of IT on patients with obstetric APS. The group of women with APS-related obstetric morbidity and IT who did not receive treatment, especially those without definite APS, had a worse prognosis in terms of a live birth. However, with SoC therapy, the prognosis is similar in those patients without IT. The association of IT with APS does not seem to predispose to the development of thrombosis during pregnancy and/or the postpartum period.

The Proper Diagnosis of Thrombophilic Status in Preventing Fetal Growth Restriction

Fetal growth restriction is an important part of monitoring a pregnancy. Because guidelines or diagnostic criteria for either minor or major thrombophilia are scarce, this systematic review aims to summarize the present knowledge in the field. We performed the CRD42022376006 protocol in Prospero with a systematic literature search in PubMed and Web of Science databases and included original full-text articles (randomized control trials and clinical trials) from the last 10 years, published in English, and with the "thrombophilia AND (pregnancy OR diagnostic criteria) AND fetal growth restriction" criteria. After two researchers extracted the articles of interest, they were assessed using the Newcastle-Ottawa Scale and eight articles were included. The elements from the thrombophilia diagnostic predict IUGR, factor V Leiden mutation, MTHFR C667T mutation, protein S deficiency, antithrombin deficiency, factor VII polymorphism, and antiphospholipid antibodies, while the association of protein C, PAI-1 and certain combinations of mutations are still under debate and require the collection of more data. The present systematic review provides an extensive picture of the actual knowledge about thrombophilia diagnosis and its links with pregnancy complications, such as intrauterine growth restriction, despite its limitation in the inclusion of other actually debated disorders such as PAI-1 mutation, protein C deficiency and other thrombophilia types.

Clinical risk factors for vasculo-placental disorders: results from a prospective case-control study nested in HEMOTHEPP French cohort study

OBJECTIVE

Determine clinical risk factors for vasculo-placental disorders in singleton pregnancies.

DESIGN

Prospective case-control study nested in HEMOTHEPP French cohort.

SETTING

Women delivered between June, 2015 and January, 2019 in any maternity ward of Finistère.

POPULATION

Cases were women with vasculo-placental disorders (pre-eclampsia, intrauterine growth restriction (IUGR), placental abruption or stillbirth). Controls were women matched for age at delivery and parity.

METHODS

Clinical data were collected by obstetricians or midwives during antenatal care visits and delivery, and recorded by trained research assistants.

MAIN OUTCOME MEASURES

Occurrence of a vasculo-placental disorder.

RESULTS

505 women with vasculo-placental disorder (299 pre-eclampsia, 253 IUGR, 44 placental abruptions, 11 stillbirths) and 1515 matched controls were selected out of 20,075 participants. In multivariable analysis, four clinical parameters were associated with pre-eclampsia: obesity (Odd ratio (OR) = 3.11, 95%CI 2.11-4.58), French overseas origin (OR = 4.41, 95%CI 1.87-10.42), previous vasculo-placental disorder (OR = 5.14, 95%CI 2.72-9.70), aspirin during pregnancy (OR = 10.10, 95%CI 1.99-51.08). Three clinical parameters were associated with IUGR: auto-immune/inflammatory disorder (OR = 3.75, 95%CI 1.83-7.68), previous vasculo-placental disorder (OR = 3.63, 95%CI 2.06-6.41), smoking during pregnancy (OR = 2.66, 95%CI 1.91- 3.71). A previous venous thromboembolism (VTE) was associated with IUGR in univariable but not in multivariable analysis (OR = 3.72, 95%CI 0.82-17.00, p = 0.09).

CONCLUSIONS

Clinical risk factors differ between IUGR and pre-eclampsia, the later, but not the former, being associated with cardiovascular risk factors.

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.

Prevalence of Factor V Leiden G1691A and Prothrombin G20210A Gene Mutation Among Pregnant Women: Experience from a Multi-Center Study in Nigeria

Introduction

Inherited thrombophilia and venous thromboembolism (VTE) have been closely linked to adverse pregnancy outcomes such as preeclampsia/eclampsia contributing to increased maternal and perinatal morbidity and mortality. There is, however, little genetic data from Africa including Nigeria that explores the prevalence of common VTE genetic risk markers such as factor V Leiden mutation (FVL G1691A) and prothrombin gene mutation (F2 G20210A) among pregnant women in Nigeria.

Purpose

To determine the prevalence and distribution of FVL G1691A and F2 G20210A in pregnant women in Lagos, Nigeria.

Patients and Methods

This hospital-based cross-sectional pilot study was conducted among pregnant women between 1 July 2019 and 31 August 2020. The genotype of interest was determined through amplification by polymerase chain reaction using G1691A of FV and prothrombin A20210G specific primers. Descriptive data were presented using Stata version 15 (Stata Corp) statistical software.

Results

Of the 400 recruited participants, 397 and 389 samples were successfully processed for FVL G1691A and F2 G20210A mutations, respectively. Three participants had FVL heterozygous mutation; thus, the prevalence of heterozygous mutation of FVL among the study participants was 0.76%, 95% CI: 0.002-0.023%, n=3/397. There was no F2 G20210A mutation detected among the study participants.

Conclusion

This study indicates that screening for factor V Leiden mutation and prothrombin gene mutation in pregnancy might not be of any clinical significance among Nigerian women. However, carrying out a genome-wide associated study is recommended to determine the true impact of these two common inherited thrombophilias in this population.

FIGO (international Federation of Gynecology and obstetrics) initiative on fetal growth: best practice advice for screening, diagnosis, and management of fetal growth restriction

Fetal growth restriction (FGR) is defined as the failure of the fetus to meet its growth potential due to a pathological factor, most commonly placental dysfunction. Worldwide, FGR is a leading cause of stillbirth, neonatal mortality, and short- and long-term morbidity. Ongoing advances in clinical care, especially in definitions, diagnosis, and management of FGR, require efforts to effectively translate these changes to the wide range of obstetric care providers. This article highlights agreements based on current research in the diagnosis and management of FGR, and the areas that need more research to provide further clarification of recommendations. The purpose of this article is to provide a comprehensive summary of available evidence along with practical recommendations concerning the care of pregnancies at risk of or complicated by FGR, with the overall goal to decrease the risk of stillbirth and neonatal mortality and morbidity associated with this condition. To achieve these goals, FIGO (the International Federation of Gynecology and Obstetrics) brought together international experts to review and summarize current knowledge of FGR. This summary is directed at multiple stakeholders, including healthcare providers, healthcare delivery organizations and providers, FIGO member societies, and professional organizations. Recognizing the variation in the resources and expertise available for the management of FGR in different countries or regions, this article attempts to take into consideration the unique aspects of antenatal care in low-resource settings (labelled “LRS” in the recommendations). This was achieved by collaboration with authors and FIGO member societies from low-resource settings such as India, Sub-Saharan Africa, the Middle East, and Latin America.

Cardiovascular risk after hypertensive disorders of pregnancy in women with and without inheritable Thrombophilia

Aim of this study was to compare cardiovascular risk in women with and without inheritable thrombophilia after hypertensive disorders of pregnancy (HDP). Blood pressure, anthropometrics and blood samples were measured 9-13 years after early-onset (<34 weeks) HDP. Amongst the 114 women included, no differences in hypertension (31.1% vs. 33.7%, OR 0.90 95% CI (0.29-2.79)), body mass index > 25 kg/m² (43.8% vs. 53.1%, OR 0.69 95% CI (0.24-2.00)) or metabolic syndrome (18.8% vs. 13.3%, OR 1.51 95% CI (0.38-6.02)) were found. These data show similar cardiovascular risk profile in women with and without inheritable thrombophilia.

A bibliometric analysis of Intrauterine Growth Restriction research

Intrauterine growth restriction (IUGR) is not a new subject in pregnancy. Nevertheless, this concept has newly begun to be integrated into pregnancy studies. We recognized articles that were published in English from 1977 to 2019 through electronic searches of the Web of Science™ database. The WoS database was searched for all published articles that compared preeclampsia from 1977 to January 2020. About 1469 documents in obstetrics and gynecology areas were analyzed in WoS database. VOSviewer software was employed to visualize the networks. The survey resulted in a 1469 published documents from 1977 to 2020. 'Gratacos' from Spain and 'Cetin' from Italy contributed the most publications. The greatest contribution came from the 'USA' (n = 498), 'Italy' (n = 155), and 'England' (n = 147). Furthermore, our results found that among these journals, the 'AJOG' (n = 318) and the 'Reproductive Sciences' (n = 209) published the largest number of papers. The top 100 most cited papers showed that 30% were reported in the 'AJOG'. About half the articles were published in the last decade and the most common studies were research paper (77%). The co-occurrence and co-citation analysis showed that the study formed four clusters. Finally, the strategic map was designed. We found that there existed an increasing trend in the large amount of publication on IUGR from 1977 to 2020. The number of studies in IUGR has substantially improved in the last decade. Authors from the 'USA' appeared the most proactive in addressing the IUGR area. By studying these articles, we propose important to support not only for grinding the IUGR challenges field but also for designing a new trend in this area.

Therapeutic Implications of Inherited Thrombophilia in Pregnancy

BACKGROUND

Inherited (hereditary) thrombophilia is a genetic disorder that affects coagulation, being responsible for more than 60% of idiopathic (spontaneous or unprovoked) thromboembolic events. Association of inherited thrombophilia with pregnancy increases the risk of thromboembolic disease, and it may be related to many complications, such as preeclampsia, recurrent miscarriage intrauterine growth restriction, early detachment of placenta, and prematurity.

AREAS OF UNCERTAINTY

Interpretation of a positive test for thrombophilia in pregnant women is difficult because they have many natural changes in the coagulation system. Genetic diagnosis of thrombophilia, after a thrombotic event or during a pregnancy complication, has a major importance, not only to define its etiology but also to determine the duration of anticoagulant treatment and risk stratification for prophylaxis treatment.

DATA SOURCES

Literature search was performed using electronic database (PubMed) between April 1981 and November 2018. We used different keywords and MeSH terms to generate the most relevant results related to the inherited thrombophilia and its impact on pregnancy.

RESULTS

Screening for inherited thrombophilia in young women is recommended in case of personal history of venous thromboembolism, first-degree relatives with a history of high-risk thrombophilia, or personal history of second-trimester miscarriage. Decision to recommend thromboprophylaxis with anticoagulant treatment in pregnant women with inherited thrombophilia is determined by history of venous thromboembolism, type and associated risk of inherited thrombophilia, and presence of additional risk factors. Low-molecular-weight heparins are the preferred agents for prophylaxis in pregnancy, while the doses vary depending on thrombophilia type, personal history, and associated risk factors.

CONCLUSIONS

Association between 2 procoagulant conditions, inherited thrombophilia and pregnancy, has an important impact for the mother and fetus. This review will summarize the impact of each inherited prothrombotic factor on cardiovascular and pregnancy outcomes and will discuss the role of anticoagulation treatment for women diagnosed with inherited thrombophilia.

ACOG Practice Bulletin No. 197: Inherited Thrombophilias in Pregnancy

Inherited thrombophilias are associated with an increased risk of venous thromboembolism and have been linked to adverse outcomes in pregnancy. However, there is limited evidence to guide screening for and management of these conditions in pregnancy. The purpose of this document is to review common thrombophilias and their association with maternal venous thromboembolism risk and adverse pregnancy outcomes, indications for screening to detect these conditions, and management options in pregnancy. This Practice Bulletin has been revised to provide additional information on recommendations for candidates for thrombophilia evaluation, updated consensus guidelines regarding the need for prophylaxis in women with an inherited thrombophilia during pregnancy and the postpartum period, and discussion of new published consensus guidelines from the Society for Obstetric Anesthesia and Perinatology addressing thromboprophylaxis and neuraxial anesthetic considerations in the obstetric population.

The association between IUGR and maternal inherited thrombophilias: A case-control study

One of the risk factors for vascular obstetric complications, such as intrauterine growth restriction (IUGR), is inherited thrombophilias. Nevertheless, routine screening for thrombophilias is not endorsed in pregnant women due to their low prevalence and conflicting results of published studies regarding the usefulness of screening in these patients. The cause of IUGR remains unknown in almost 1 quarter of cases. There are no published studies evaluating the association of inherited thrombophilias and IUGR in patients with IUGR of unknown origin. Understanding and preventing IUGR is an important public health concern, as IUGR has been associated with fetal mortality and neonatal morbidity, as well as adverse long-standing consequences. This study aimed to evaluate the prevalence of inherited thrombophilias in IUGR of unknown cause and to test the association between the inherited thrombophilias and IUGR of unknown cause.This study included 33 cases of IUGR of unknown cause tested for inherited thrombophilias and 66 controls individually matched for age, ethnicity, and smoking status.Patients with plasminogen activator inhibitor 1 (PAI-1) and methylenetetrahydrofolate reductase (MTHFR) had significantly higher odds for IUGR of unknown cause (P < .001 and P = .002, respectively) with OR 13.546 (CI 95% 3.79-48.37) and 8.139 (CI 95% 2.20-30.10), respectively. A positive association between other inherited thrombophilias (homozygous 20210 prothrombin gene mutation and homozygous factor V Leiden) and IUGR of unknown cause was also found, P = .096, OR 6.106 (CI 95% 0.72-51.30), although it was not statistically significant (P = .096, OR = 6.106, CI 95% 0.72-51.30).Our results indicate that PAI-1 and MTHFR thrombophilias represent risk factors for IUGR of otherwise unidentified cause.

Adverse pregnancy outcomes and inherited thrombophilia

AIM

(1) To evaluate the prevalence of inherited thrombophilia in pregnant women with adverse pregnancy outcomes: intrauterine growth retardation (IUGR), preeclampsia (PE) and placental abruption. (2) To assess the impact of inherited thrombophilia on the nature of obstetric complications. (3) To assess levels of protein S, protein C, antithrombin III and homocysteine in pregnant women with adverse pregnancy outcomes.

SUBJECTS AND METHODS

The study comprised 162 pregnant women. The patients were divided into three test groups and one control group. In all 162 patients the following tests were completed: activated protein C resistance (APC-R), the level of free protein S, activity of protein C, antithrombin III and the level of homocysteine. The data were statistically analyzed via χ2 of independence or homogeneity test.

RESULTS

In 32 of 162 patients participating in clinical research thrombophilia was diagnosed (10 patients with APC-R, 21 patients with protein S deficiency, one patient with hyperhomocysteinemia): seven patients belonged to the control group and 25 patients had diagnosed adverse pregnancy outcomes (P=0.04). In 32 patients with diagnosed thrombophilia, level of protein S was decreased (P=0.04). Protein S deficiency was diagnosed, when level of protein S was lower than 30% in the second trimester and lower than 24% in the third trimester. The incidence of activated protein C resistance caused by the mutation of factor V Leiden was in six patients (5.9%) with adverse pregnancy outcomes, and in four patients (6.6%) from the control group. Results were not statistically significant. No protein C deficiency was diagnosed (diagnosis: level<60%), but in 50% of patients with thrombophilia level of protein C was over the norm (P=0.02). The level of antithrombin III was often decreased in patients with preeclampsia - (32.4%), then in the other patients - (17.2%) (P=0.04), but no patient was diagnosed with antithrombin III deficiency (diagnosis: level<60%).

CONCLUSIONS

Tests for thrombophilia should be carried out in women with adverse pregnancy outcomes in their history, who are planning pregnancy, to start anticoagulant prophylaxis. Our study supports the thesis that tests for thrombophilia should be carried out in women with a history of adverse pregnancy outcomes and who are planning a pregnancy to start anticoagulant prophylaxis.

Effects of multiple inherited and acquired thrombophilia on outcomes of in-vitro fertilization

INTRODUCTION

The effects of multiple inherited and acquired thrombophilic defects on the outcome of in-vitro fertilization (IVF) remain unexplored. The aim of this study was to evaluate the association between multiple thrombophilia and clinical outcomes in a large prospective cohort of women undergoing IVF.

MATERIALS AND METHODS

Consecutive women scheduled for IVF were eligible. The primary study outcome was live birth. Secondary outcomes included spontaneous abortion, clinical pregnancy, and symptomatic venous thromboembolism.

RESULTS

687 women with a mean age of 34.6 (±3.2) years were included. Overall, 22 women (3.2%) had two or more thrombophilic defects. The probability of live birth was not statistically significantly different between women with ≥2 thrombophilia (odds ratio [OR] 0.62; 95% confidence interval [CI], 0.18 to 2.11) or ≥1 thrombophilia (OR 0.67;95% CI, 0.41 to 1.09) and women without any thrombophilia. None of the individual inherited thrombophilia nor positivity to antiphospholipid antibodies or lupus anticoagulant were associated with live birth. Single positivity for lupus anticoagulant carried a more than threefold higher risk of abortion (OR 3.74; 95% CI, 1.30 to 10.75). There were no statistically significant associations between individual or multiple thrombophilic defects and clinical pregnancy or pregnancy test results. No woman had a history of venous thromboembolism and none developed a thrombotic event during the study.

CONCLUSIONS

In women undergoing IVF, the presence of two or more thrombophilic defects was rare and showed no statistically significant associations with IVF outcomes.

Association Between Factor V Leiden Mutation, Small for Gestational Age, and Preterm Birth: A Systematic Review and Meta-Analysis

OBJECTIVE

To estimate the association of a maternal factor V Leiden (FVL) mutation with SGA and preterm birth.

DATA SOURCES

We performed a search of PubMed, Embase, Scopus, CINAHL, and the Cochrane Library from inception to April 2016 for cohort and case-control studies of women with FVL mutation and associated outcomes of SGA and preterm birth that included a reference group without FVL mutation. Additional studies were identified from reference lists of relevant research and review articles.

STUDY SELECTION

Two authors (JKB, AMO) independently examined the abstracts of the potentially eligible studies, and full texts of eligible studies were retrieved for further evaluation. Disagreements were resolved by consensus. We identified 42 studies suitable for inclusion in the meta-analysis.

DATA EXTRACTION

Thirty-two studies evaluated SGA, and 18 studies assessed preterm birth. Study quality was assessed using the Newcastle Ottawa Scale. A random effects model with inverse variance weighting was used to calculate pooled ORs and 95% CIs. Subgroup analyses were performed by study design.

DATA SYNTHESIS

The overall OR associating FVL mutation with SGA was significant (OR 1.40, 95% CI 1.18 to 1.67). Analysis of 13 cohort studies resulted in an OR of 1.20 (95% CI 1.03 to 1.41), and data from 19 case-control studies yielded an OR of 1.86 (95% CI 1.35 to 2.56). There was no significant association between FVL mutation and preterm birth (OR 1.17, 95% CI 1.00 to 1.37) when all groups were studied, but the association was significant for case-control studies alone (OR 1.40, 95% CI 1.05 to 1.86).

CONCLUSION

There is an increased risk for SGA in pregnancies complicated by FVL mutation in both cohort and case-control study designs. The risk of preterm birth with FVL mutation is less clear, although there is conflicting evidence from cohort and case-control studies regarding the risk of preterm birth associated with FVL mutation.

Genetic markers for inherited thrombophilia are associated with fetal growth retardation in the population of Central Russia

AIM

The aim of this study was to examine the role of hereditary thrombophilia in the development of fetal growth retardation (FGR) in the population of Central Russia.

METHODS

The case-control study sample included 497 women in the third trimester of pregnancy recruited during 2009-2013. The participants were enrolled into two groups: patients with FGR (n = 250) and controls without FGR (n = 247). The participants were genotyped for four genetic markers of hereditary thrombophilia: factor V Leiden (G > A FV, rs6025), prothrombin (G > A FII, rs1799963), factor VII (G > A FVII, rs6046), and fibrinogen (G > A FI, rs1800790).

RESULTS

The genetic factors for an increased risk of FGR were allele G of rs6046 (odds ratio [OR] = 2.34) and genotype GG of rs6046 (OR = 2.64), whereas genotype GA of rs6046 had the protective value (OR = 0.42). A combination of alleles G of rs1799963, A of rs6046, and G of rs1800790 (OR = 0.31) reduces the risk of FGR.

CONCLUSION

Polymorphism rs6046 of the FVII gene is associated with the development of FGR.

Associations between Maternal and Fetal Inherited Thrombophilias, Placental Characteristics Associated with Vascular Malperfusion, and Fetal Growth

Pregnancy results in alterations in coagulation processes, which may increase the risk of thrombosis. Inherited thrombophilia mutations may further increase this risk, possibly through alterations in the placenta, which may result in pregnancy complications such as poor fetal growth. The purpose of our study is to evaluate the association of fetal growth, approximated by birth weight for gestational age percentile, with genetic markers of thrombophilia and placental characteristics related to vascular malperfusion. We analyzed data from the Stillbirth Collaborative Research Network's population-based case-control study conducted in 2006-2008. Study recruitment occurred in five states: Rhode Island and counties in Massachusetts, Georgia, Texas, and Utah. The analysis was restricted to singleton, nonanomalous live births ≤42 weeks' gestation with a complete placental examination and successful testing for ≥1 thrombophilia marker (858 mothers, 902 infants). Data were weighted to account for oversampling, differential consent, and availability of placental examination. We evaluated five thrombophilia markers: factor V Leiden, factor II prothrombin, methylenetetrahydrofolate reductase A1298C and C677T, and plasminogen activator inhibitor type 1 in both maternal blood and placenta/cord blood. We modeled maternal and fetal thrombophilia markers separately using linear regression. Maternal factor V Leiden mutation was associated with a 13.16-point decrease in adjusted birth weight percentile (95% confidence interval: -25.50, -0.82). Adjustment for placental abnormalities related to vascular malperfusion did not affect the observed association. No other maternal or fetal thrombophilia markers were significantly associated with birth weight percentile. Maternal factor V Leiden may be associated with fetal growth independent of placental characteristics.

Anticoagulants to prevent recurrent placenta-mediated pregnancy complications: Is it time to put the needles away?

Placenta-mediated pregnancy complications, such as pre-eclampsia, placental abruption, birth of a small-for-gestational age infant and late pregnancy loss, are common and carry significant morbidity and mortality. The etiology of placenta-mediated pregnancy complications is likely multifactorial and may include abnormal coagulation activation of the maternal-fetal interface. The use of antepartum low-molecular-weight heparin (LMWH) prophylaxis to prevent recurrent placenta-mediated pregnancy complications has become common practice despite limited and conflicting evidence to support its use. This paper reviews the evidence, including recently published data from an individual patient level meta-analysis, which challenges the role of LMWH in preventing recurrent placenta-mediated pregnancy complications. Incorporating this recent evidence, we recommend against the use of LMWH to prevent recurrent placenta-mediated pregnancy complications in women with and without inherited thrombophilia.

Cardiovascular risk factors in women with inheritable thrombophilia a decade after single or recurrent hypertensive disorder of pregnancy

OBJECTIVE

To described cardiovascular risk factors in women with inheritable thrombophilia 8-19 years after early-onset hypertensive disorders of pregnancy (HD) with or without recurrent HD.

METHODS

Women with recurrent HD were compared with women with single HD, for physical examination and cardiovascular parameters in serum.

RESULTS

Systolic blood pressure, diastolic blood pressure, and albumin: creatinine ratio were higher in women with recurrent HD compared with women with single HD (p = 0.046, p = 0.029, and p = 0.008, respectively). In both groups 72.7% had an increased cardiovascular risk.

CONCLUSION

Women with inheritable thrombophilia after single or recurrent HD have a high cardiovascular risk.

Is thrombophilia associated with placenta-mediated pregnancy complications? A prospective cohort study

BACKGROUND

Case control studies suggest that genetic thrombophilias increase the risk of placenta-mediated pregnancy complications (pregnancy loss, small for gestational age (SGA), preeclampsia and/or placental abruption). Cohort studies have not supported this association but were underpowered to detect small effects.

OBJECTIVE

To determine if factor V Leiden (FVL) or the prothrombin gene mutation (PGM) were associated with placenta-mediated pregnancy complications.

PATIENTS/METHODS

A prospective cohort of unselected, consenting pregnant women at three Canadian tertiary care hospitals had blood drawn in the early second trimester and were genotyped for FVL and PGM after delivery. The main outcome measure was a composite of pregnancy loss, SGA < 10th percentile, preeclampsia or placental abruption.

RESULTS

Complete primary outcome and genetic data were available for 7343 women. Most were Caucasian (77.7%, n = 5707), mean age was 30.4 (± 5.1) years, and half were nulliparous. There were 507 (6.9%) women with FVL and/or PGM; 11.64% had a placenta-mediated pregnancy complication. Of the remaining 6836 women, 11.23% experienced a complication. FVL and/or PGM was associated with a relative risk of 1.04 (95% CI, 0.81-1.33) for the composite outcome, with similar results after adjustment for important covariates.

CONCLUSIONS

Carriers of FVL or PGM are not at significantly increased risk of these pregnancy complications.

Inherited thrombophilias and adverse pregnancy outcomes: a review of screening patterns and recommendations

Historically, much controversy has existed regarding the association of inherited thrombophilias with adverse pregnancy outcomes. The current guidelines do not recommend screening unless a personal history of venous thromboembolism is present, but the authors' survey of physician screening patterns has suggested that up to 40% of physicians may screen contrary to the current guidelines. This article summarizes the existing evidence for each inherited thrombophilia and reviews the current 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.

[Hereditary thrombophilias and placental-mediated pregnancy complications in the II./III. trimester]

Placental-mediated pregnancy complications (PmC) like preeclampsia, intrauterine growth restriction and placental abruption are common causes of fetal and maternal morbidity and mortality. The high prevalence of hereditary thrombophilias in case-control studies associated with pathological morphological findings of the placenta in these cases gave evidence for the association between hereditary thrombophilias and PmC. However, data from the literature are inconsistent, since subsequent prospective cohort studies could not demonstrate significant associations between inherited thrombophilia and PmC. Because of the multifactorial aetiology of PmC it may be difficult to prove, that hereditary thrombophilias are independent risk factors for PmC. Current guidelines do not recommend screening for inherited thrombophilias in patients with previous PmC. Evidence from current in vitro studies have shown, that heparin has beneficial non-anticoagulatory effects on trophoblast invasion. Retrospective case-control studies and recently published randomised controlled cohort studies have shown, that prophylactic administration of low-molecular-weight heparin (LWH), started in early pregnancy, may lead to a significant reduction in the incidence of PmC in subsequent pregnancies in patients with and without hereditary thrombophilias and previous PmC.

CONCLUSION

Large, well-designed multicenter studies are needed to elucidate the role of hereditary thrombophilias in cases of PmC and to confirm the benefit of LWH for subsequent pregnancy outcomes.

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.

Coagulation disorders in pregnancy: acquired and inherited thrombophilias

Both acquired and inherited thrombophilias are associated with an increased risk of pregnancy-related venous thromboembolism (VTE) as well as with adverse pregnancy outcome. However, the extension of attributable risk for each thrombophilia and outcome is still a question of debate. Thrombophilias have been investigated in connection with VTE and pregnancy complications such as: recurrent and nonrecurrent early pregnancy loss, late fetal death, placental abruption, fetal growth restriction, and preeclampsia. This review discusses the evidence of association between thrombophilias and pregnancy outcome together with issues as to clinical management and preventive strategies.

Obesity and diabetes genes are associated with being born small for gestational age: results from the Auckland Birthweight Collaborative study

Background

Individuals born small for gestational age (SGA) are at increased risk of rapid postnatal weight gain, later obesity and diseases in adulthood such as type 2 diabetes, hypertension and cardiovascular diseases. Environmental risk factors for SGA are well established and include smoking, low pregnancy weight, maternal short stature, maternal diet, ethnic origin of mother and hypertension. However, in a large proportion of SGA, no underlying cause is evident, and these individuals may have a larger genetic contribution.

Methods

In this study we tested the association between SGA and polymorphisms in genes that have previously been associated with obesity and/or diabetes. We undertook analysis of 54 single nucleotide polymorphisms (SNPs) in 546 samples from the Auckland Birthweight Collaborative (ABC) study. 227 children were born small for gestational age (SGA) and 319 were appropriate for gestational age (AGA).

Results and Conclusion

The results demonstrated that genetic variation in KCNJ11, BDNF, PFKP, PTER and SEC16B were associated with SGA and support the concept that genetic factors associated with obesity and/or type 2 diabetes are more prevalent in those born SGA compared to those born AGA. We have previously determined that environmental factors are associated with differences in birthweight in the ABC study and now we have demonstrated a significant genetic contribution, suggesting that the interaction between genetics and the environment are important.

The association of factor V leiden and prothrombin gene mutation and placenta-mediated pregnancy complications: a systematic review and meta-analysis of prospective cohort studies

BACKGROUND

Factor V Leiden (FVL) and prothrombin gene mutation (PGM) are common inherited thrombophilias. Retrospective studies variably suggest a link between maternal FVL/PGM and placenta-mediated pregnancy complications including pregnancy loss, small for gestational age, pre-eclampsia and placental abruption. Prospective cohort studies provide a superior methodologic design but require larger sample sizes to detect important effects. We undertook a systematic review and a meta-analysis of prospective cohort studies to estimate the association of maternal FVL or PGM carrier status and placenta-mediated pregnancy complications.

METHODS AND FINDINGS

A comprehensive search strategy was run in Medline and Embase. Inclusion criteria were: (1) prospective cohort design; (2) clearly defined outcomes including one of the following: pregnancy loss, small for gestational age, pre-eclampsia or placental abruption; (3) maternal FVL or PGM carrier status; (4) sufficient data for calculation of odds ratios (ORs). We identified 322 titles, reviewed 30 articles for inclusion and exclusion criteria, and included ten studies in the meta-analysis. The odds of pregnancy loss in women with FVL (absolute risk 4.2%) was 52% higher (OR = 1.52, 95% confidence interval [CI] 1.06-2.19) as compared with women without FVL (absolute risk 3.2%). There was no significant association between FVL and pre-eclampsia (OR = 1.23, 95% CI 0.89-1.70) or between FVL and SGA (OR = 1.0, 95% CI 0.80-1.25). PGM was not associated with pre-eclampsia (OR = 1.25, 95% CI 0.79-1.99) or SGA (OR 1.25, 95% CI 0.92-1.70).

CONCLUSIONS

Women with FVL appear to be at a small absolute increased risk of late pregnancy loss. Women with FVL and PGM appear not to be at increased risk of pre-eclampsia or birth of SGA infants. Please see later in the article for the Editors' Summary.

Inherited thrombophilia polymorphisms and pregnancy outcomes in nulliparous women

OBJECTIVE

To estimate the association between five commonly inherited thrombophilia polymorphisms and adverse pregnancy outcomes in women who had no prior history of adverse pregnancy outcomes or personal or family history of venous thromboembolism.

METHODS

Healthy nulliparous women (n=2,034) were recruited to this prospective cohort study before 22 weeks of gestation. Genotyping for factor V Leiden, prothrombin gene mutation, methylenetetrahydrofolate reductase enzyme (MTHFR) C677T, MTHFR A1298C, and thrombomodulin polymorphism was performed. Clinicians caring for women were blinded to the results of thrombophilia tests. The primary composite outcome was the development of severe preeclampsia, fetal growth restriction, placental abruption, stillbirth, or neonatal death.

RESULTS

Complete molecular results and pregnancy outcome data were available in 1,707 women. These complications were experienced by 136 women (8.0%). Multivariable logistic regression demonstrated two statistically significant findings. Women who carried the prothrombin gene mutation had an odds ratio of 3.58 (95% confidence interval [CI] 1.20-10.61, P=.02) for the development of the composite primary outcome. Homozygous carriers of the MTHFR 1298 polymorphism had an odds ratio of 0.26 (95% CI 0.08-0.86, P=.03). None of the other polymorphisms studied showed a significant association with the development of the primary outcome in this cohort of women.

CONCLUSION

Prothrombin gene mutation confers an increased risk for the development of adverse pregnancy outcomes in otherwise asymptomatic, nulliparous women, whereas homozygosity for MTHFR 1298 may protect against these complications. The majority of asymptomatic women who carry an inherited thrombophilia polymorphism have a successful pregnancy outcome.

LEVEL OF EVIDENCE

II.

Anticoagulants to prevent placenta-mediated pregnancy complications: a review of current evidence

PURPOSE OF REVIEW

Placenta-mediated pregnancy complications are relatively common and are associated with significant morbidity and mortality. Although anticoagulants are increasingly being used to prevent these complications, the evidence supporting their use is limited. This article will focus on reviewing the current evidence base for the use of anticoagulants to prevent placenta-mediated pregnancy complications in women with or without identifiable thrombophilia.

RECENT FINDINGS

Controversy exists whether inherited or acquired thrombophilias cause placenta-mediated complications. Small randomized studies with methodological limitations suggest that antepartum anticoagulant prophylaxis will reduce pregnancy loss in women with both acquired and inherited thrombophilia and prior pregnancy loss. There are no published randomized controlled trials examining anticoagulant prophylaxis in thrombophilic women with prior preeclampsia, intrauterine growth restriction or placental abruption. More recently, the benefit of antepartum anticoagulant prophylaxis in women without thrombophilia with prior placenta-mediated pregnancy complications has been suggested in a small pilot randomized trial.

SUMMARY

Overall, although antepartum anticoagulant prophylaxis has the potential to reduce placenta-mediated pregnancy complications in women with and without identifiable thrombophilia, the data generated by these trials are methodologically limited and inadequate. Hence, we conclude that further trials are required prior to adopting the use of antepartum anticoagulant prophylaxis to prevent placenta-mediated pregnancy complications in routine clinical practice.

Preventing thrombophilia-related complications of pregnancy

Pregnancy is associated with an increased risk of venous thromboembolism (VTE) and approximately half of all pregnancy-related VTEs are associated with thrombophilia. Recent studies suggest that there is a link between thrombophilia and other adverse pregnancy outcomes, such as fetal loss, preeclampsia, placental abruption and intrauterine growth restriction. However, the associations reported are modest, and high quality data are limited. Although the most compelling data derive from pregnant women with antiphospholipid antibodies, the use of anticoagulants for the prevention of pregnancy complications other than VTE in women with heritable thrombophilias is becoming more frequent. In this article, we review the impact of the various thrombophilias on pregnancy and its outcome, the evidence for therapies aimed at prevention of thrombophilia-related pregnancy complications, and briefly discuss the role of screening for thrombophilia in pregnancy.

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.