Hereditary Thrombophilia and Recurrent Pregnancy Loss

The relevance of prothrombotic genetic variants in women who experienced pregnancy loss or embryo implantation failure: A retrospective analysis of 1922 cases

OBJECTIVE

The aim of our study was that to assess the allelic and genotype frequencies of nine prothrombotic gene variants in patients with a history of pregnancy loss and recurrent pregnancy loss (RPL). Women who underwent assisted reproductive technology (ART) with ongoing pregnancy and those with recurrent implantation failure (RIF) were also included.

METHODS

Nine prothrombotic gene variants were evaluated: factor V Leiden (FVL), factor V, H1299R variant (FVR2), factor II (FII) G20210A, methylene-tetrahydrofolate reductase (MTHFR) C677T and A1298C, beta-fibrinogen -455G>A, factor XIII (FXIII) V34L, human platelet antigen-1 (HPA-1) L33P variants, and plasminogen activator inhibitor-1 (PAI-1) 4G/5G. The following study groups were assessed: (1) women who experienced one (n = 334) or two (n = 264) episodes of pregnancy loss; (2) 468 women who experienced RPL; (3) 214 women who underwent ART followed by ongoing pregnancies; and (4) 282 women who experienced RIF after ART, that is, three or more consecutive implantation failures following high-quality embryo transfers to the uterus with an appropriate endometrium. As control group, 430 subjects from the general population were enrolled.

RESULTS

FVL, the -455G>A variant of beta-fibrinogen, and PAI-1 4G were associated with a higher risk of developing RPL compared with the general population. Furthermore, FVL, FVR2, FII G20210A and MTHFR C677T conferred a significantly higher risk of RIF in women who performed ART compared with the general population. No statistical differences between the general population and other study groups were observed.

CONCLUSIONS

Specific prothrombotic genetic variants are more frequently expressed in women with RPL and RIF, supporting their role in the development of polimicrothrombosis and impairing the invasion during embryo implantation.

Recurrent MiscarriageGreen-top Guideline No. 17

In this guideline, recurrent miscarriage has been defined as three or more first trimester miscarriages. However, clinicians are encouraged to use their clinical discretion to recommend extensive evaluation after two first trimester miscarriages, if there is a suspicion that the miscarriages are of pathological and not of sporadic nature. Women with recurrent miscarriage should be offered testing for acquired thrombophilia, particularly for lupus anticoagulant and anticardiolipin antibodies, prior to pregnancy. [Grade C] Women with second trimester miscarriage may be offered testing for Factor V Leiden, prothrombin gene mutation and protein S deficiency, ideally within a research context. [Grade C] Inherited thrombophilias have a weak association with recurrent miscarriage. Routine testing for protein C, antithrombin deficiency and methylenetetrahydrofolate reductase mutation is not recommended. [Grade C] Cytogenetic analysis should be offered on pregnancy tissue of the third and subsequent miscarriage(s) and in any second trimester miscarriage. [Grade D] Parental peripheral blood karyotyping should be offered for couples in whom testing of pregnancy tissue reports an unbalanced structural chromosomal abnormality [Grade D] or there is unsuccessful or no pregnancy tissue available for testing. [GPP] Women with recurrent miscarriage should be offered assessment for congenital uterine anomalies, ideally with 3D ultrasound. [Grade B] Women with recurrent miscarriage should be offered thyroid function tests and assessment for thyroid peroxidase (TPO) antibodies. [Grade C] Women with recurrent miscarriage should not be routinely offered immunological screening (such as HLA, cytokine and natural killer cell tests), infection screening or sperm DNA testing outside a research context. [Grade C] Women with recurrent miscarriage should be advised to maintain a BMI between 19 and 25 kg/m2 , smoking cessation, limit alcohol consumption and limit caffeine to less than 200 mg/day. [Grade D] For women diagnosed with antiphospholipid syndrome, aspirin and heparin should be offered from a positive test until at least 34 weeks of gestation, following discussion of potential benefits versus risks. [Grade B] Aspirin and/or heparin should not be given to women with unexplained recurrent miscarriage. [Grade B] There are currently insufficient data to support the routine use of PGT-A for couples with unexplained recurrent miscarriage, while the treatment may carry a significant cost and potential risk. [Grade C] Resection of a uterine septum should be considered for women with recurrent first or second trimester miscarriage, ideally within an appropriate audit or research context. [Grade C] Thyroxine supplementation is not routinely recommended for euthyroid women with TPO who have a history of miscarriage. [Grade A] Progestogen supplementation should be considered in women with recurrent miscarriage who present with bleeding in early pregnancy (for example 400 mg micronised vaginal progesterone twice daily at the time of bleeding until 16 weeks of gestation). [Grade B] Women with unexplained recurrent miscarriage should be offered supportive care, ideally in the setting of a dedicated recurrent miscarriage clinic. [Grade C].

Maternal candidate gene variants, epigenetic factors, and susceptibility to idiopathic recurrent pregnancy loss: A systematic review

BACKGROUND

Recurrent pregnancy loss is defined as the loss of two or more pregnancies and is a distressing condition for couples.

OBJECTIVE

To investigate the relationship between variants in the candidate susceptibility genes and epigenetic factors to identify risk factors for idiopathic recurrent pregnancy loss (iRPL).

SEARCH STRATEGY

A systematic literature search was performed using PubMed, Google Scholar, ScienceDirect, and Scopus databases. Insilico analysis was carried out using ShinyGO and STRING software.

SELECTION CRITERIA

Research papers examining the association between variations in genetic and epigenetic factors and iRPL.

DATA COLLECTION AND ANALYSIS

Data were independently extracted by two authors.

MAIN RESULTS

In total, 83 research papers were finally selected for the present study. Among all the genes involved in the pathogenesis of recurrent pregnancy loss, polymorphisms in IL superfamily genes, VEGF, ESR, and MTHFR were the most investigated.

CONCLUSION

Polymorphisms in angiogenesis, immune tolerance, and thrombophilia pathway genes, which occur independently or synergistically, may lead to various complications during fetal development. Identification of multi-allele risk variants and epigenetic factors in women will be helpful in the identification of high-risk pregnancies.

PROSPERO REGISTRATION NUMBER

Prospero CRD42021287315.

Maternal Thrombophilic and Hypofibrinolytic Genetic Variants in Idiopathic Recurrent Pregnancy Loss: a Continuing Mystery

Despite the fact that multiple recurrent pregnancy loss (RPL) etiologies have been identified, 50-70% of RPL cases remain enigmatic, and idiopathic RPL is still a serious medical challenge. A plethora of studies have investigated the correlation of RPL with variations in coagulation and/or fibrinolytic factors-encoding genes. Notwithstanding, evidence for a link between these variations and RPL remains discordant. We aimed to explore the association of thrombophilic and hypofibrinolytic gene variations with RPL development. Two hundred Saudi women were recruited in this study, comprising 150 women experiencing RPL and 50 healthy women. Thirteen genetic variants, including FV G1691A, FV A4070G, F2 G20210A, F13A1 G103T, FGB - 455G > A, PAI-1 - 675 4G/5G, ITGB3 T1565C, MTHFR C677T, MTHFR A1298C, ACE I/D, APOB G10708A, APOE T388C, and APOE C526T were genotyped using ViennaLab StripAssay. Women experiencing RPL harbor significantly higher frequencies of the F13A1 103 T, FGB - 455A, and ITGB3 1565C alleles than control women (p < 0.001). No differences in the prevalence of other investigated variants were identified between control women and those with RPL. No considerable link of F5 1691G > A/4070A > G, MTHFR 677C > T/1298A > C, and APOE 388 T > C/526C > T haplotypes with RPL risk was demonstrated. F13A1 G103T, FGB - 455G > A, and ITGB3 T1565C variants are connected to a higher likelihood of developing RPL and, hence, may have the potential to identify those women at risk of RPL, thereby, improving RPL susceptibility prediction. Incorporating molecular testing of thrombophilic and hypofibrinolytic genetic variants into routine workup could confer a promising approach for refined RPL risk assessment.

Chinese Herbal Medicines Have Potentially Beneficial Effects on the Perinatal Outcomes of Pregnant Women

Introduction: Tocolytic treatment is beneficial to pregnant women with a risk of premature labor or miscarriage. However, previous reports have shown that progestogen might not be effective and ritodrine may increase the risk of maternal vascular-related diseases. Chinese herbal products (CHP) are used as alternative therapies for pregnant women. The goal was to evaluate the efficacy of combined tocolytic therapy and CHP therapy in pregnancy outcomes for pregnant women in Taiwan.

Materials and Methods: We conducted a retrospective cohort study based on the National Health Insurance Research Database. A total of 47,153 pregnant women treated with tocolytics aged 18–50 years from 2001 to 2015 were selected from two million random samples. According to the medical use of tocolytics and CHP, we divided the users into two groups: western medicine (WM) only (n = 40,961) and WM/CHP (n = 6,192) groups. A propensity score (PS)-matched cohort (6,192 pairs) was established based on baseline confounders. All participants were followed up to perinatal outcomes. Conditional logistic regression analysis was used to examine the effects of CHP use on the odds of miscarriage and preterm birth.

Results: The adjusted odds ratio (OR) for premature birth in the WM/CHP group (n = 411, 6.64%) was significantly lower than in the WM group (n = 471, 7,61%) (0,86, 95% confidence interval [CI], 0.74–0.99). Further subgroup analysis based on the usage of formulae that activate blood and remove stasis or purgative formulae, the adjusted OR of preterm birth of those using these formulae was significantly lower in the WM/CHP group (n = 215, 6.32%) than that in the WM group (n = 265, 7.77%) (OR: 0.79, 95% CI: 0.65–0.96).

Conclusion: We found that the combination of CHP and tocolytics can be beneficial to pregnant women in the prevention of premature birth. Further research is required to investigate causal relationships.

Genetic markers for inherited thrombophilia related pregnancy loss and implantation failure in Indian population - implications for diagnosis and clinical management

AIM

The biology of recurrent pregnancy loss and recurrent implantation failure (RPL-RIF) is complex with multi-factorial etiology, with defective thrombosis being one of the most important and highly prevalent causes. The role of several thrombophilia related genes and variants associated with RPL-RIF is widely reported, and this study aimed to identify the risk associated with these genes in the Indian population.

METHODS

Next generation sequencing (NGS) was employed for the current study. NGS enables sequencing of multiple genes, identification of new variants, and establishment of genetic correlations with reproductive failure in diverse population groups. The present NGS based study evaluates association of twenty-nine genotypes of ten coagulation pathway genes (F2, F5, F13, MTR, MTRR, MTHFR, ANXA5, PROZ, SERPINE1 and VEGFA) with RPL-RIF in 540 female subjects - 474 patients with early recurrent pregnancy loss, late pregnancy loss, pregnancy complications in late gestation and recurrent implantation failure, with 66 controls.

RESULTS

The results emphasize inclusion of genotypes of seven thrombophilia genes (MTHFR, MTRR, MTR, ANXA5, PROZ, SERPINE1, VEGFA) for diagnosis of inherited thrombophilia risk for RPL-RIF in Indian population, as against the common practice of testing limited to F2, F5 and MTHFR genes.

CONCLUSION

Deriving risk magnitude from Combined Risk Analysis and interpretation of high-risk haplotypes are crucial components for evidence based personalized management such as selection of drugs and dosage, and prenatal or pre-implantation recommendations, for high-risk patients in fertility and obstetric clinics.

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.

May the morphological findings in the first-trimester abortion materials be indicative of inherited thrombophilia?

PURPOSE

İnherited thrombophilia is associated with severe pregnancy complications including recurrent spontaneous abortion. In the light of this strong association, the impact of thrombophilic mutations on the placenta and their morphological reflections has aroused attention of both clinicians and pathologists. In the present study, we aimed to show the association between placental abnormalities with thrombophilia by examining the morphological findings in a wide range of first-trimester chorionic villi.

METHODS

We performed a histological examination on the abortion specimens obtained from 129 patients with recurrent pregnancy losses that were evaluated with respect to inherited thrombophilia based on the presence of Factor V Leiden (G1691A), Prothrombin G20210A and methylenetetrahydrofolate reductase (MTHFR) C677T gene mutations detected by genetic analysis. Abortion materials either with and without thrombophilia were evaluated in terms of the morphological parameters such as hydropic change, vascularity, fibrosis, fibrinoid degeneration, Hofbauer macrophage, syncytiotrophoblast knotting, villitis, calcification, villous contour and villous size, hemorrhage, thrombus, proliferation of trophoblasts, villous stromal or villous vascular karyorrhexis.

RESULTS

No statistically significant difference was found between the patient groups with and without thrombophilia in terms of morphological findings except vascularity of chorionic villi. The avascular chorionic villi (<3 vessels per villus) were found in 62.9% and 16.9% obtained from the women with and without thrombophilic mutation, respectively. This difference was statistically significant (P < 0.001).

CONCLUSION

As a conclusion, it could be stated that the analysis of morphological findings in the abortion specimen is not a time-wasting process. Particularly, data related with vascularity of chorionic villi would be precious and beneficial. We suggest that highlighting the presence of avascular villi in the pathology report as a parameter would be guiding for clinicians regarding the impact of the thrombophilic gene mutations.

The Prevalence and Impact of Polycystic Ovary Syndrome in Recurrent Miscarriage: A Retrospective Cohort Study and Meta-Analysis

Background: The use of different definitions and diagnostic approaches of polycystic ovary syndrome (PCOS) and recurrent miscarriage (RM) has led to a wide range of prevalence rates in the literature. Despite the persistent controversy about the factual prevalence of PCOS in RM, a vast number of studies have revealed evidence about their association with each other. The goals of this study were to evaluate the prevalence of polycystic ovarian morphology and PCOS within the RM population, performing meta-analyses with the obtained data from this study, together with previous reports on this topic and evaluating reproductive outcome in women with RM and PCOS. Methods: A retrospective cohort study with 452 women with RM and a meta-analysis were conducted. The main outcome parameter was the prevalence of PCOS in RM patients. Results: In the retrospective study, the prevalence of PCOS in RM was 9.5%. Negative results for the selected risk factors for RM were present in 283 patients (62.6%). From all evaluated possible underlying causes for RM, only the presence of thrombophilic disorders was significantly associated with PCOS (PCOS: 20.9% versus no PCOS: 7.8%, p = 0.010). In the meta-analysis of three studies on PCOS in RM patients, which used the revised Rotterdam criteria for defining PCOS, an estimated pooled prevalence of 14.3% (95% CI: 6.2–24.9) was found. In the retrospective data set, women in the PCOS group revealed significantly higher luteinizing hormone (LH), testosterone, and Anti-Mullerian hormone (AMH) levels than age- and body mass index (BMI)-matched controls with RM negative for the selected risk facotrs (p < 0.05). The rate of further miscarriages was significantly higher in PCOS women than in controls (71.4% versus 53.6%, respectively; p = 0.031). Conclusions: The prevalence of PCOS seems slightly increased in women with RM. Women with PCOS suffering from RM showed a significantly higher risk for further miscarriage and decreased chances of having a life birth of about 18% which did not reach statistical significance. Therefore, we assume that PCOS plays a moderate role in RM.

Prescription patterns and factors influencing the use of Chinese herbal medicine among pregnant women in Taiwan: a population-based retrospective study

BACKGROUND

The use of Chinese herbal medicine (CHM) has been widely promoted as a natural and safe way to treat illness during pregnancy. However, prescription patterns and factors influencing its use are largely unknown. Therefore, we conducted a population-based study to address these questions.

METHODS

Pregnant women aged 18-50 years were selected from Taiwan's National Health Insurance Research Database between 2001 to 2011. CHM prescriptions and diagnostic records were collected. Demographic data and pre-existing diseases were compared between CHM users and non-users. A multivariate logistic regression analysis was performed to identify possible factors influencing the use of CHM during pregnancy.

RESULTS

A total of 81,873 eligible prescription records were identified, and 16,553 pregnant women were prescribed CHM during pregnancy, yielding a CHM prescription rate of 20.2%. The three most frequently used herbs were Scutellariae Radix (Huang Qin) (4.4%), Eucommiae cortex (Du Zhong) (2.5%), and Atractylodes Rhizome (Bai Zhu) (2.4%). The most frequently used herbal formulae were Dang-Guei-Shao-Yao-San (4.1%), Jia-Wei-Xiao-Yao-San (3.5%), and Xiang-Sha-Liu-Jun-Zi-Tang (2.6%). Multivariate logistic regression revealed that subjects with an older age, a university education, a pre-pregnancy history of CHM use, asthma, chronic renal disease, and cardiac valvular disease and living in a residential area other than northern Taiwan had an increase in adjusted odds ratio for CHM use during pregnancy.

CONCLUSIONS

In this population-based study, we found that demographic factors and pre-existing diseases were associated with the use of CHM among pregnant women. It is worth noting that Leonuri Herba (Yi Mu Cao) and Shao-Fu-Zhu-Yu-Tang should be used with caution in the first trimester. Further research is needed to explore the safety and effectiveness of the use of CHM in pregnant women.

Perinatal complications related to inherited thrombophilia: review of evidence in different regions of the world

The term thrombophilia describes disorders associated with an increased predisposition of developing venous thromboembolism (VTE). It may be acquired, like in those with antiphospholipid syndrome or inherited. The aim of this review was to compare the complications and outcomes of pregnancies in women with inherited thrombophilia between different populations, including the population of our country where the results of the research are scarce. The review of literature included all papers indexed on PubMed and Medline in the last 20 years, with different study design, including other reviews of literature, systematic reviews with meta-analysis and several case-control studies and population-based cohort studies. We aimed to cover as many geographic regions as possible with the aim to show the differences in the different parts of the world and including our country. Our analysis showed that types of thrombophilia differ in different geographic regions. Also, the differences exist between one particular type of thrombophilia in different regions. Nevertheless, no matter what the differences are between prevalence, all authors investigated the association between inherited thrombophilia and poor pregnancy outcome and managed to find some kind of association. The case with our own country is similar. Although we lack in studies with this issue and the design of published studies is not powerful enough, we may conclude that in our samples, women with thrombophilia are in potential risk of several poor pregnancy outcomes. Further and better analyses are necessary to prove this hypothesis not only on the level of study sample but also on general population. Given the fact that thrombophilia certainly affects the pregnancy and its outcome, the urge to perform screening tests in every woman suspected to have this kind of disorder and with respect to differences that exist in different world regions is inevitable.

Analysis of PROC and PROS1 single nucleotide polymorphisms in a thrombophilia family

OBJECTIVE

The aim of this study was to assess the association of single nucleotide polymorphisms (SNPs) in protein C (PROC) and protein S (PROS1) genes with deep venous thrombosis (DVT) in a thrombophilia family.

METHODS

DNA were extracted from blood of participants. Five PROC SNPs and 11 PROS1 SNPs were selected from the Hapmap and 1000 Genomes databases. The minor allele frequencies (MAFs) of SNPs in the thrombophilia family (Group I) and healthy controls (Group II) were detected. SNPs were analysed by Chi-square, logistic regression and linkage disequilibrium patterns.

RESULTS

MAFs for all 16 SNPs were greater than 0.05. Chi-square analysis showed significant differences between Group I and Group II in the frequency of mutant alleles of rs1799808, rs5936, rs6123, rs12634349, rs6441600 and rs13062355 SNPs (P < .05). Logistic regression analysis found that mutant alleles of rs1799808, rs6441600 and rs13062355 SNPs may contribute to DVT in this family (OR > 1, L95 > 1). Linkage disequilibrium was found among 15 of the PROC and PROS SNPs.

CONCLUSIONS

Single nucleotide polymorphisms (SNPs) of PROC and PROS1 may be closely associated with DVT in this thrombophilia family. Mutant alleles of rs1799808, rs6441600 and rs13062355 SNPs may contribute to DVT, whereas mutant alleles of rs1799810, rs6123 and rs12634349 may protect individuals from DVT. With the exception of rs9681204, there was linkage disequilibrium between PROC and PROS1 SNPs. We found that 12 haplotypes were in linkage disequilibrium, but linkage disequilibrium was strong in only eight of these (frequency >5%).

Polymorphisms of methalenetetrahydrofolate reductase in recurrent pregnancy loss: an overview of systematic reviews and meta-analyses

PURPOSE

The aim is to summarize and evaluate current systematic reviews and meta-analyses on MTHFR polymorphisms in recurrent pregnancy loss (RPL).

METHODS

We searched Pubmed and Embase databases and selected in form of PICOS (participants, interventions, comparisons, outcomes, and study design). Our methodology was registered on PROSPERO (CRD42017042762). Systematic reviews and meta-analyses containing primary studies were extracted for meta-analyses, along with their OR and 95%CI. We assessed the quality of the included studies using AMSTAR and OQAQ criteria.

RESULTS

Eleven systematic reviews and meta-analyses were identified. C677T was significantly related to RPL overall in Allele (OR, 95%CI 1.43, 1.29-1.60), Recessive (OR, 95%CI 1.66, 1.42-1.95), and Homozygous (OR, 95%CI 2.08, 1.66-2.61). There was no correlation observed between A1298C and RPL, except for in Heterozygous (OR, 95%CI 1.62, 1.17-2.25).

CONCLUSIONS

We identified a difference in the association between MTHFR C677T polymorphism and RPL, especially in Asian population. No significant correlation was found between A1298C and RPL.

The obstetric complications in women with hereditary thrombophilia

All congenital thrombophilias are associated with an increased risk of venous thromboembolism (VTE) during pregnancy. Several studies have confirmed the increased risk of obstetric complications in women with congenital thrombophilias. Case-control, cohort and transversal studies have shown that hereditary thrombophilia is more prevalent in the cohorts of women with pregnancy losses, early onset preeclampsia, abruptio placentae and IUGR. However, despite the increase in the relative risk, the absolute risk of VTE and adverse pregnancy outcomes is low. There is convincing evidence that the deficiency of natural anticoagulants (AT, protein C, protein S) is a risk factor for late fetal loss. The mutations of the FVL (G1691A) gene and the prothrombin (G20210A) gene are associated with a double risk for unexplained RPL and non-recurrent late fetal loss. The association of congenital thrombophilia and preeclampsia is much more uncertain, being, probably, limited to the FVL G1691A gene mutation and more severe cases of preeclampsia. Fewer data are available for IUGR and abruptio placentae. In addition, genetic and epidemiological research suggest that obstetric complications during pregnancy have a polygenic multifactorial etiology, with a risk determined by the interaction of multiple genetic variants and other risk factors.

Effect of multiple thrombophilic gene mutations on uterine artery blood flow in nonpregnant recurrent pregnancy loss patients: are we searching enough?

Objective: To investigate whether multiple thrombophilic mutations had a significant effect on uterine artery blood flow of nonpregnant recurrent pregnancy loss (RPL) patients.Materials and methods: Among 71 RPL patients, FV Leiden (FV), prothrombin G20210A (PTGM) and MTHFR mutations, deficiency of protein S, protein C and antithrombin III (AT3), association of Val34Leu polymorphism of the FXIII (FXIII), 4G/5G polymorphism of plasminogen activator inhibitor (PAI), -455-G/A polymorphism of β-fibrinogen (fibrinogen), and HPA-1 a/b L33P polymorphism of GPIIIa (GPIIIa) genes were investigated. Doppler flow measurements of RPL patients and healthy controls were performed at mid-luteal phase.Results: Twenty-two patients who had no thrombophilic gene mutations were grouped as unexplained RPL. Also, while 25 patients had multiple mutations, 24 patients had single mutation. In the multiple mutation RPL group, the most frequent mutations were PAI (22%), MTHFR C677T (20%), MTHFR A1298C (19%), and fibrinogen (11%). Only in the multiple mutation RPL group, mean PI and dominant PI values were significantly higher than the control group.Conclusions: Our data showed negative effects of multiple thrombophilic gene mutations on uterine artery blood flow and clarified the different effects of single and multiple thrombophilic factors on uterine artery vasculature. It is concluded that investigating more thrombophilic mutations could ameliorate prognostic factors of RPL and interactions to improve uterine artery blood flow could bring benefit to obstetric outcome.