Frequency of selected thrombophilias in women with placental abruption

The role of thrombophilias in reproduction: A swot analysis

Thrombophilia is a group of inherited or acquired coagulation disorders that have been associated with reproductive failure. However, there are still no clear recommendations on whether its inclusion in the initial study of the infertile couple or patients with recurrent implantation failure is necessary. In this discussion paper, based on a SWOT (strengths, weaknesses, opportunities, threats) analysis, the different aspects of the repercussions of thrombophilia screening and treatment in reproduction are evaluated. To avoid possible subjectivity in the analysis and results of this study, researchers followed Oxford criteria for the evaluation of evidence. The results from the evaluation of the reviewed bibliography seem to indicate that, pending new evidence, it would be advisable not to include thrombophilia screening in the initial baseline study of the infertile couple. There is no evidence to support a clear association between thrombophilia and implantation failure or infertility. Thrombophilia testing in this setting may increase cost, with minimal potential benefit and lead to inappropriate use of anticoagulants with possible deleterious adverse effects. Future well-designed studies are needed to assess the possible benefit of anticoagulant therapy in infertile thrombophilic patients with implantation failure.

Association of MTHFR 677C>T polymorphism with IUGR and placental abruption risk: A systematic review and meta-analysis

OBJECTIVE

The effects of the MTHFR 677C > T polymorphism on the intrauterine growth restriction (IUGR) and placental abruption risk have been evaluated in some studies. However, those studies results were conflicting and ambiguous. Therefore, we carried out the current meta-analysis to evaluate the association of MTHFR 677C > T polymorphism with risk of IUGR and placental abruption from all eligible studies.

METHODS

An electronic search of the PubMed, Embase, Scopus and CNKI databases was performed up to February 25, 2020.

RESULTS

A total of 25 case-control studies including eight studies with 687 cases and 2336 controls for IUGR and 17 studies with 1574 cases and 5758 controls for placental abruption were selected. The analysis results indicated that MTHFR 677C > T polymorphism was associated with an increased risk of IUGR and placental abruption in global population. When stratified by ethnicity a significant association between the MTHFR 677C > T polymorphism and IUGR risk was found in Caucasians and Africans. However, there was no a significant association between the MTHFR 677C > T polymorphism and placental abruption risk by ethnicity.

CONCLUSIONS

Our pooled data indicated that the MTHFR 677C > T polymorphism might play a role in development of IUGR and placental abruption.

Comparison of 2 approaches in management of pregnant women with inherited trombophilias: Prospective analytical cohort study

Previous adverse pregnancy outcomes (APO) in women with hereditary thrombophilia have emerged as new indications for prophylactic use of low-molecular-weight heparin (LMWH) during pregnancy. Recent meta-analysis conducted to establish if LMWH may prevent recurrent placenta-mediated pregnancy complications point to important therapeutic effect but these findings are absolutely not universal. Furthermore, previous studies regarding LMWH prophylaxis for APO in women with inherited thrombophilia were performed in high risk patients with previous adverse health outcomes in medical, family and/or obstetric history. Therefore, the aim of this study was to investigate the effects of LMWH prophylaxis on pregnancy outcomes in women with inherited thrombophilias regardless of the presence of previous adverse health outcomes in medical, family, and obstetric history.Prospective analytical cohort study included all referred women with inherited thrombophilia between 11 and 15 weeks of gestation and followed-up to delivery. Patients were allocated in group with LWMH prophylaxis (study group) and control group without LWMH prophylaxis. The groups were compared for laboratory parameters and Doppler flows of umbilical artery at 28 to 30th, 32nd to 34th and 36th to 38th gestational weeks (gw), and for obstetric and perinatal outcomes.The study group included 221 women and control group included 137 women. Mean resistance index of the umbilical artery Ri in 28 to 30, 32 to 34, and 36 to 38 gw were significantly higher in the control group compared to study group (0.71 ± 0.02 vs 0.69 ± 0.02; 0.67 ± 0.03 vs 0.64 ± 0.02; and 0.67 ± 0.05 vs 0.54 ± 0.08, respectively). Intrauterine fetal death (IUFD) and miscarriages were statistically significantly more frequent in control group compared to the patients in study (P < .001). The frequencies of fetal growth restriction (FGR) and APO were significantly higher in the control group compared to the study group (P = .008 and P < .001, respectively). In a multivariate regression model with APO as a dependent variable, only Ri was detected as a significant protective factor for APO, after adjusting for age and LMWH prophylaxis (P < .001).We have demonstrated better perinatal outcomes in women with LMWH prophylaxis for APO compared to untreated women.

Stillbirth and factor V Leiden - A regional based prospective evaluation

BACKGROUND

Approximately 10% of Swedes are carriers of coagulation factor V Leiden (FVL). It has been suggested that carriers are at an increased risk of stillbirth. We aimed to assess the risk of stillbirth in carriers of FVL as compared to non-carriers.

METHODS

A consecutive registration of all stillbirths from 2001 to 2015 in the whole Stockholm region has been performed. A FVL blood sample, an autopsy and histopathological examination of the placenta was scheduled to be offered all women with stillbirth. Main outcome was the difference in carriership of FVL between cases with live- vs. stillbirth. The primary cause of death was determined according to the Stockholm hierarchical classification of stillbirth.

RESULTS

The incidence of stillbirth was 3.6‰. Out of the 1392 cases of stillbirth occurring during the study period, FVL status was determined in 963 women. Of these 74 (7.7%) were carriers of FVL as compared to 8.1% in the control group (p = 0.6). A primary cause of death due to infection was twice as common among non-carriers compared to carriers of FVL (odds ratio [OR] = 2.3, 95% CI 1.08-4.8). In the whole study group, the prevalence of SGA was 14-fold increased among stillbirths as compared to live births (OR = 13.9, 95% CI 12.4-15.6).

CONCLUSION

Maternal FVL carriership was not related to an increased risk of stillbirth. However, a diagnosis of primary cause of death due to infection was less likely among FVL carriers.

Prevalence of genetic prothrombotic risk factors: 1691G > A FV, 20210G > A PT and 677C > T MTHFR mutations in the Bosnian population

BACKGROUND

Venous thrombosis (VT) affects 1-2 out of 10(3) individuals each year. Mutations of 1691G > A FV gene, 20210G > A PT gene and 677C > T gene MTHFR are common in Europe and increase the risk of venous thrombosis. To the authors' knowledge, this is the first report on the prevalence of these mutations in the general population of Bosnia and Herzegovina.

AIM

The aim of this study was to simultaneously analyse main VT associated polymorphisms and compare the results with those published for other European populations.

DATA SOURCES

Electronic databases including Medline and Embase were searched from 1995 to December 2013.

SUBJECTS AND METHODS

The subjects of the study consisted of 100 unrelated healthy people from Bosnia and Herzegovina (82 female and 18 male). The mean age of the cohort was 58.8 (± 10.7) years. PCR-RFLP was used for measurement of allele frequencies.

RESULTS

All three SNPs were found to be polymorphic, with allele frequencies of 6.0%, 6.0% and 37.5% for 1691A FV, 20210A PT and 677T MTHFR, respectively.

CONCLUSION

Further studies on larger cohorts with an adequate female-to-male ratio are necessary to confirm a high prevalence of hereditary thrombophilia in the Bosnian population.

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.

Inherited thrombophilia: diagnosis and anticoagulation treatment in pregnancy

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

[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 mutation and its impact on pregnancy complications

OBJECTIVE

The aim of this prospective study was to find the association between the factor V Leiden mutation and adverse pregnancy outcomes.

METHODS

This study is an analysis of a prospective observational study of the frequency of placenta-mediated complications of factor V Leiden mutation carriers. We compared pregnancy outcomes of 11 women with a heterozygous form of the factor V Leiden mutation with 41 women of a control group.

RESULTS

All pregnancies ended with delivery of a living infant. None of the 52 pregnancies were complicated by venous thromboembolism. There were a few significant differences regarding placenta-mediated complications. The gestational age at delivery showed small significant differences. There was a significant difference in the birth weight deviation in percentage between FVL carriers and controls. The incidence of blood loss exceeding 1000 ml was higher in the control group.

CONCLUSIONS

Carriership of the factor V Leiden mutation did not affect the incidence of preeclampsia. Adverse pregnancy outcomes such as placental abruption were rare. Eclampsia, intrauterine fetal death and venous thromboembolism did not occur. Our results provide evidence that the maternal heterozygous FVL mutation did not increase the risk of an adverse pregnancy outcome.

Humans, mice, and mechanisms of intestinal atresias: a window into understanding early intestinal development

INTRODUCTION

Intestinal atresias have long been hypothesized to result from either failure of recanalization of the intestinal lumen or in utero vascular accidents. Recent work in animal models is now calling for a reassessment of these widely held paradigms.

PURPOSE

In this review, we will examine the data that led to the original hypotheses and then evaluate more recent work challenging these hypotheses. Furthermore, we will discuss how defining the mechanism of atresia formation in animal models may provide insight into early intestinal development and the mechanism of lengthwise intestinal growth.

CONCLUSION

Such insight will be critical in developing regenerative therapies for patients with intestinal failure.

Factor V Leiden mutation and pregnancy-related complications

OBJECTIVE

The objective of the study was to determine the prevalence of the factor V Leiden (FVL) mutation and its association with obstetric complications, blood loss during delivery, and venous thromboembolism (VTE).

STUDY DESIGN

This was a prospective, observational, case-cohort study of 491 FVL carriers and 1055 controls derived from 6003 screened women. Data were analyzed with a Student t test and cross-tabulation.

RESULTS

FVL carriership prevalence was 8.3%. Gestational age at delivery, birthweight deviation, gestational hypertension, and preeclampsia incidences did not differ between groups. The incidences of placental abruption, neonatal asphyxia, eclampsia, intrauterine fetal death, intrapartum death, and unexplained late miscarriage were low. The incidence of major blood loss at delivery was lower in carriers. There were 3 VTEs among carriers and none among controls.

CONCLUSION

FVL carriership did not influence pregnancy-induced hypertension, birthweight, or prematurity but raised the risk of venous thromboembolism and lowered the risk of major blood loss.

Polymorphisms in thrombophilia and renin-angiotensin system pathways, preterm delivery, and evidence of placental hemorrhage

OBJECTIVE

The purpose of this study was to analyze functional polymorphisms in candidate genes (methylenetetrahydrofolate reductase [MTHFR]677C>T, MTHFR1298A>C, factor 5 1691G>A [FVL], and angiotensinogen (AGT)-6G>A) in relation to a hypothesized placental hemorrhage pathway to preterm delivery (PTD).

STUDY DESIGN

We assessed maternal genotypes, pregnancy outcomes, and placental pathologic evidence among 560 white and 399 black women who were recruited at mid trimester into a prospective cohort study (1998-2004). Odds of dominant genotypes were calculated for PTDs with (n = 56) or without (n = 177) evidence of placental hemorrhage (referent = term) with the use of race-stratified polytomous logistic regression models.

RESULTS

Among white women, FVL GA/AA and AGT(-6) GA/AA were both associated with hemorrhage-related PTDs (odds ratio [OR], 4.8; 95% confidence interval [CI], 1.6-14.2 and OR, 3.8; 95% CI, 1.3-10.5, respectively), but not other PTDs (ORs, 1.2 and 0.9, respectively). FVL GA/AA was associated with placental abruption (OR, 5.8; 95% CI, 1.1-30) among white women. All results were null for MTHFR genotypes.

CONCLUSION

FVL and AGT variant genotypes were associated specifically with hemorrhage-related PTDs.

Thrombophilia risk factors are associated with intrauterine foetal death and pregnancy-related venous thromboembolism

Pregnancy in healthy women is accompanied by hypercoagulable changes that may interact with thrombophilia risk factors and threaten pregnancy. However, the literature on this issue is conflicting. In investigating the relationship between pregnancy-associated complications and the presence of thrombophilia risk factors, we studied the records of 414 women who had been examined for inherited and acquired thrombophilia in the period 1996 to 2006 because of pregnancy-associated complications. Of a total of 885 pregnancies among the women, 397 were recorded as foetal loss/intrauterine foetal death during the first (62 %), second (25 %) or third trimester (13 %). One-hundred-and-two (25 %) women had had a thromboembolic event during one of their pregnancies, and 98 (24 %) had had pre-eclampsia on at least one occasion. Intrauterine growth restriction was found in 105 (25 %) of the women, and 29 (7 %) suffered placental abruption. We found that 120 (29 %) women had at least one thrombophilia risk factor. Factor V Leiden heterozygosity was the most common thrombophilia factor (n = 52), mostly linked with the risk of venous thromboembolism during pregnancy or postpartum and to foetal death during the second or third trimester. Fifty-three (13 %) women had antiphospholipid antibodies (lupus anticoagulant and/or anti-beta2-glycoprotein 1 antibodies) mainly associated with the risk of spontaneous abortion during the first trimester. In conclusion, thrombophilia was found to be considerably more common in women with pregnancy-associated complications in comparison with the general population, and most frequently in conjunction with venous thromboembolism during pregnancy and the postpartum period.

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.

Postpartum thromboembolism: severe events might be preventable using a new risk score model

Background:

Pregnancy-related venous thromboembolism (VTE) is a major cause of maternal morbidity and mortality. A new risk assessment model for VTE in relation to pregnancy has been introduced in Sweden. We wished to determine the proportion of preventable VTE cases if the model had been in use and make a brief cost-benefit analysis.

Methods:

A hospital-based retrospective case-control study of all postpartum thromboembolic instances of deep venous thrombosis and pulmonary embolisms during a 16-year period. Large anamnestic risk factors at the time of delivery were assessed. We correlated the findings with the new Swedish guidelines for thromboprophylaxis.

Results:

We found 37 cases of postpartum VTE during the study period. Nineteen of all VTE cases (51%) and eight out of eleven of cases of pulmonary embolism (73%) had two or more large anamnestic risk factors, ie, they would have been subjected to thromboprophylaxis if the new guidelines had been used. The cost of each preventable VTE was lower than treating a VTE.

Conclusion:

Approximately one-half of postpartum VTE cases and 70% of pulmonary emboli cases have at least two large risk factors and might be preventable using the new algorithm. From the perspective of the health care system the new recommendations appears to be cost-effective.

Thrombophilia and adverse pregnancy outcome

This article focuses on the clinical evaluation and management of women who have thrombophilia-related placental vascular complications, including fetal loss, pre-eclampsia, intrauterine fetal growth restriction, and placental abruption. All are major causes of maternal and fetal adverse outcomes.