Inherited thrombophilia in infertile women: implication in unexplained infertility

Evidence-based guideline: unexplained infertility†

STUDY QUESTION

What is the recommended management for couples presenting with unexplained infertility (UI), based on the best available evidence in the literature?

SUMMARY ANSWER

The evidence-based guideline on UI makes 52 recommendations on the definition, diagnosis, and treatment of UI.

WHAT IS KNOWN ALREADY

UI is diagnosed in the absence of any abnormalities of the female and male reproductive systems after 'standard' investigations. However, a consensual standardization of the diagnostic work-up is still lacking. The management of UI is traditionally empirical. The efficacy, safety, costs, and risks of treatment options have not been subjected to robust evaluation.

STUDY DESIGN, SIZE, DURATION

The guideline was developed according to the structured methodology for ESHRE guidelines. Following formulation of key questions by a group of experts, literature searches, and assessments were undertaken. Papers written in English and published up to 24 October 2022 were evaluated.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Based on the available evidence, recommendations were formulated and discussed until consensus was reached within the guideline development group (GDG). Following stakeholder review of an initial draft, the final version was approved by the GDG and the ESHRE Executive Committee.

MAIN RESULTS AND THE ROLE OF CHANCE

This guideline aims to help clinicians provide the best care for couples with UI. As UI is a diagnosis of exclusion, the guideline outlined the basic diagnostic procedures that couples should/could undergo during an infertility work-up, and explored the need for additional tests. The first-line treatment for couples with UI was deemed to be IUI in combination with ovarian stimulation. The place of additional and alternative options for treatment of UI was also evaluated. The GDG made 52 recommendations on diagnosis and treatment for couples with UI. The GDG formulated 40 evidence-based recommendations-of which 29 were formulated as strong recommendations and 11 as weak-10 good practice points and two research only recommendations. Of the evidence-based recommendations, none were supported by high-quality evidence, one by moderate-quality evidence, nine by low-quality evidence, and 31 by very low-quality evidence. To support future research in UI, a list of research recommendations was provided.

LIMITATIONS, REASONS FOR CAUTION

Most additional diagnostic tests and interventions in couples with UI have not been subjected to robust evaluation. For a large proportion of these tests and treatments, evidence was very limited and of very low quality. More evidence is required, and the results of future studies may result in the current recommendations being revised.

WIDER IMPLICATIONS OF THE FINDINGS

The guideline provides clinicians with clear advice on best practice in the care of couples with UI, based on the best evidence currently available. In addition, a list of research recommendations is provided to stimulate further studies in the field. The full guideline and a patient leaflet are available in www.eshre.eu/guideline/UI.

STUDY FUNDING/COMPETING INTEREST(S)

The guideline was developed by ESHRE, who funded the guideline meetings, literature searches, and dissemination of the guideline in collaboration with the Monash University led Australian NHMRC Centre of Research Excellence in Women's Health in Reproductive Life (CREWHIRL). The guideline group members did not receive any financial incentives; all work was provided voluntarily. D.R. reports honoraria from IBSA and Novo Nordisk. B.A. reports speakers' fees from Merck, Gedeon Richter, Organon and Intas Pharma; is part of the advisory board for Organon Turkey and president of the Turkish Society of Reproductive Medicine. S.B. reports speakers' fees from Merck, Organon, Ferring, the Ostetric and Gynaecological Society of Singapore and the Taiwanese Society for Reproductive Medicine; editor and contributing author, Reproductive Medicine for the MRCOG, Cambridge University Press; is part of the METAFOR and CAPE trials data monitoring committee. E.B. reports research grants from Roche diagnostics, Gedeon Richter and IBSA; speaker's fees from Merck, Ferring, MSD, Roche Diagnostics, Gedeon Richter, IBSA; E.B. is also a part of an Advisory Board of Ferring Pharmaceuticals, MSD, Roche Diagnostics, IBSA, Merck, Abbott and Gedeon Richter. M.M. reports consulting fees from Mojo Fertility Ltd. R.J.N. reports research grant from Australian National Health and Medical Research Council (NHMRC); consulting fees from Flinders Fertility Adelaide, VinMec Hospital Hanoi Vietnam; speaker's fees from Merck Australia, Cadilla Pharma India, Ferring Australia; chair clinical advisory committee Westmead Fertility and research institute MyDuc Hospital Vietnam. T.P. is a part of the Research Council of Finland and reports research grants from Roche Diagnostics, Novo Nordics and Sigrid Juselius foundation; consulting fees from Roche Diagnostics and organon; speaker's fees from Gedeon Richter, Roche, Exeltis, Organon, Ferring and Korento patient organization; is a part of NFOG, AE-PCOS society and several Finnish associations. S.S.R. reports research grants from Roche Diagnostics, Organon, Theramex; consulting fees from Ferring Pharmaceuticals, MSD and Organon; speaker's fees from Ferring Pharmaceuticals, MSD/Organon, Besins, Theramex, Gedeon Richter; travel support from Gedeon Richter; S.S.R. is part of the Data Safety Monitoring Board of TTRANSPORT and deputy of the ESHRE Special Interest Group on Safety and Quality in ART; stock or stock options from IVI Lisboa, Clínica de Reprodução assistida Lda; equipment/medical writing/gifts from Roche Diagnostics and Ferring Pharmaceuticals. S.K.S. reports speakers' fees from Merck, Ferring, MSD, Pharmasure. HRV reports consulting and travel fees from Ferring Pharmaceuticals. The other authors have nothing to disclose.

DISCLAIMER

This guideline represents the views of ESHRE, which were achieved after careful consideration of the scientific evidence available at the time of preparation. In the absence of scientific evidence on certain aspects, a consensus between the relevant ESHRE stakeholders has been obtained. Adherence to these clinical practice guidelines does not guarantee a successful or specific outcome, nor does it establish a standard of care. Clinical practice guidelines do not replace the need for application of clinical judgment to each individual presentation, nor variations based on locality and facility type. ESHRE makes no warranty, express or implied, regarding the clinical practice guidelines and specifically excludes any warranties of merchantability and fitness for a particular use or purpose. (Full disclaimer available at www.eshre.eu/guidelines.).

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.

The Pathophysiology of Hypercoagulability and Infertility

Alongside an interplay of a multitude of factors, attainment of a favorable pregnancy outcome is predicated on successful implantation, which in itself is a complex process anchored by balanced interchange with the hemostatic system. Among other etiologies, failure of implantation can result in infertility, and lead affected couples to consider assisted reproductive technology (ART) in an effort to fulfill their desire for procreation. Given the critical role of the hemostatic system in the process of implantation, documentation of a hypercoagulable state during controlled ovarian stimulation in the context of in vitro fertilization, as well as the potential association of its derangement in the setting of thrombophilia, with infertility, ART, ovarian hyperstimulation syndrome, and failure of implantation are explored. Additionally, current evidence addressing the relationship between ART and thromboembolism is examined, as is the role of therapy with heparin and aspirin to decrease thrombotic risk and improve ART-related pregnancy outcomes. Evidence-based recommendations from relevant professional societies are summarized.

Evolving paradigm in thrombophilia screening

: The role of genetic thrombophilia screening for identifying a hypercoagulable state in the management of venous thromboembolism. We searched MEDLINE and EMBASE from 1995 to 2017, the websites of the professional bodies including American Society of Hematology, British Society of Hematology, International Society of Thrombosis and Hemostasis, College of American Pathologists, American College of Medical Genetics, and American Society of obstetrics and gynecology for their clinical practice guidelines. We used search strategy terms - venous thromboembolism, inherited, thrombophilia, and hypercoagulable state. Thrombophilia screening does not alter management in pregnancy, infertility, recurrent miscarriages, in primary occlusive arterial syndromes, and for primary prevention in relatives of venous thromboembolism patients considering hormonal manipulation including oral contraceptives. Routine thrombophilia screening for identifying a hypercoagulable state is not indicated in venous thromboembolism, as it is only useful in a select group of patients. There is no difference in the treatment of venous thromboembolism in patients with or without an inherited hypercoagulable state.

Reduced Protein C Global Assay Levels in Infertile Women with in vitro Fertilization Failure: A Pilot Study

Protein C global is a global dotting assay that evaluates abnormalities in the protein C anticoagulant pathway. A few studies have examined this assay in relation to assisted reproductive technology (ART), but its role in infertile women with in vitro fertilization (IVF) failure remains unclear. In this study, we assessed protein C in infertile women with a history of IVF failure who were undergoing ART. We examined 45 healthy fertile women who conceived naturally, and 45 infertile women with 2 or more implantation failures undergoing ART. Both protein C and activated protein C resistance (APC-R) were evaluated. The results showed that mean protein C expressed as a normalized ratio (PCAT-NR) was significantly lower in the study group compared to the control group (0.76 ± 0.15 vs. 0.91 ± 0.14, respectively; p = 0.0001). Follow-up on ART outcomes showed that women who failed ART had significantly lower PCAT-NR compared to successful cases. PCAT-NR did not correlate with APC-R levels in the study (r = 0.125, p < 0.5) or failed ART subgroups. Using logistic regression analysis, patients with lower PCAT-NR levels showed an elevated risk of implantation failure (p = 0.04, OR 0.50, 95% CI 0.26-0.84). In conclusion, protein C global assay may play a role in the etiology of IVF failure, which might be independent of APC-R. Larger studies are encouraged to validate these findings and explore the underlying pathophysiological mechanisms.

Which are the most common thrombophilic genetic nucleotide polymorphisms in infertile women undergoing an IVF cycle?

INTRODUCTION

Thrombophilia is considered one of the causes of infertility, especially after repeated failures of IVF techniques. The aim of this work is to evaluate the incidence of thrombophilia in women who underwent IVF cycles and assess the outcome of the techniques.

METHODS

In vivo study. The study sample was composed of 262 women undergoing a fresh cycle of in vitro fertilization (IVF) cycle of Intracytoplasmatic Sperm Injection (ICSI) from July 2012 to December 2014 in the Center of Physiopathology of Human Reproduction. Amongst these patients, we have selected 96 patients with indication for thrombophilia screening.

RESULTS

Thrombophilia screening detects that only 8% (n = 8) of the patients was negative to all the studied mutations, while the remaining 92% (n = 88) was positive to at least one mutation. The most common mutations were MTHFR gene (C677T) (91,84%), ACE gene (54,88%) and PAI-1 gene (69,44%).

CONCLUSION

Our results showed an increased frequency of genetic nucleotide polymorphisms in women reporting failures in IVF techniques. Differently from scientific literature data, in our work, the most frequent mutation affects the enzyme gene MTHFR, particularly the C667T mutation; on the other side, mutations of factor V and II are less common.

Identifying existing Choosing Wisely recommendations of high relevance and importance to hematology

Choosing Wisely (CW) is a medical stewardship initiative led by the American Board of Internal Medicine Foundation in collaboration with professional medical societies in the United States. In an effort to learn from and leverage the work of others, the American Society of Hematology CW Task Force developed a method to identify and prioritize CW recommendations from other medical societies of high relevance and importance to patients with blood disorders and their physicians. All 380 CW recommendations were reviewed and assessed for relevance and importance. Relevance was assessed using the MORE(TM) relevance scale. Importance was assessed with regard to six guiding principles: harm avoidance, evidence, aggregate cost, relevance, frequency and impact. Harm avoidance was considered the most important principle. Ten highly relevant and important recommendations were identified from a variety of professional societies. Recommendations focused on decreasing unnecessary imaging, blood work, treatments and transfusions, as well as on increasing collaboration across disciplines and considering value when recommending treatments. Many CW recommendations have relevance beyond the society of origin. The methods developed by the ASH CW Task Force could be easily adapted by other Societies to identify additional CW recommendations of relevance and importance to their fields. Am. J. Hematol. 91:787-792, 2016. © 2016 Wiley Periodicals, Inc.

Inherited thrombophilia and reproductive disorders

Apart from its established role in the pathogenesis of venous thromboembolism (VTE), inherited thrombophilia has been proposed as a possible cause of pregnancy loss and vascular gestational complications. There is a lot of controversy in the literature on the relationship between inherited prothrombotic defects and these obstetric complications. This is a review of the literature on inherited thrombophilia and reproductive disorders. Factor V Leiden, prothrombin G20210A mutation, and protein S deficiency seem to be associated with late and recurrent early pregnancy loss, while their impact on other pregnancy complications is conflicting. No definite association has been established between protein C and antithrombin deficiency and adverse pregnancy outcome, primarily due to their low prevalence. Screening is suggested only for women with early recurrent loss or late pregnancy loss. Anticoagulant treatment during pregnancy should be considered for women with complications who were tested positive for thrombophilia.

Etiological risk factors for subfertility among Palestinian women in Gaza

The inability to procreate is frequently considered a personal tragedy and a hardship for couples, impacting on the entire family and even the local community. In Gaza strip, Palestine, there has been no study on etiological risk factors for subfertility. The present study aimed to identify risk factors associated with subfertility among women in Gaza, Palestine. One hundred and sixty-nine women in the study group and 115 women in the control group were included. Cases were selected randomly from those referred to the Al Basma Fertility Center, Gaza, Palestine. Data were collected through close-ended questionnaire, sonography, hormonal analysis and thrombophilia profile that included the methylenetetrahydrofolate reductase (MTHFR 677 C > T), factor V leiden (1691 G > A) and prothrombin (20210 G > A) genes. By using univariate analyses, the effects of different patient-related variables on the presence of subfertility were evaluated. A multiple logistic regression model was constructed, crude and adjusted odds ratios (OR) and 95% confidence intervals (95% CI) were calculated. The findings showed that 73.5 % (169/230) of the women referred to the Al Basma Center sought treatment for subfertility. Different etiological risk factors were associated with subfertility, the most frequent of which in descending order were: thrombophilic disorders, fallopian tube problems, sex hormone abnormalities and polycystic ovary syndrome with an adjusted OR of 21.42, 13.63, 11.69 and 10.29, respectively. In conclusion, several etiological risk factors are responsible for subfertility among women in Gaza. Comprehensive evaluation of infertile women should be considered in the course of treatment; otherwise, the duration of sterility may be extended.

Unexplained infertility: association with inherited thrombophilia

INTRODUCTION

Unexplained infertility represents one of the most common diagnoses in fertility care. Attention is being paid to the association between inherited thrombophilia and infertility causes. In this study we investigated the prevalence of inherited thrombophilia according to infertility causes.

MATERIALS AND METHODS

We studied Prothrombin gene G20210A mutation, Factor V Leiden, deficiencies in protein S and C and antithrombin in 930 Caucasian infertile women referred to Fertility Center of the Department of Sciences for Woman and Child's Health, University of Florence, of whom 230 with unexplained, 195 female and 283 male infertility, and in 240 women who have conceived naturally without hormonal stimulation therapy.

RESULTS

A significant relationship between inherited thrombophilia [OR 95%CI 1.97 (1.05-3.68), p = 0.03] and unexplained infertility was observed, whereas no association between thrombophilia and female and male infertility was found. Significantly higher prevalence of prothrombin gene mutation in unexplained infertile women in comparison to that observed in fertile women was observed (5.7% vs 2.1% p = 0.04); the prevalence of the other thrombophilia determinants was higher, even if not significantly, in the unexplained infertile group.

CONCLUSIONS

This study demonstrates the relationship between inherited thrombophilia and unexplained infertility, thus suggesting the contribution of genetic components in modulating unexplained infertility, behind anovulation, male and tubal factor.

Association between Thrombophilia and Repeated Assisted Reproductive Technology Failures

PURPOSE

This study was performed to investigate the incidence of thrombophilic gene mutations in repeated assisted reproductive technology (ART) failures.

METHODS

The prevalence of mutated genes in the patients with a history of three or more previous ART failures was compared with the patients with a history of successful pregnancy following ARTs. The study group included 70 patients, 34 with three or more previously failed ARTs (A) and control group consisted of 36 patients with successful pregnancy following ARTs (B). All patients were tested for the presence of mutated thrombophilic genes including factor V Leiden (FVL), Methylenetetrahydrofolate reductase (MTHFR) and Prothrombin (G20210A) using real-time polymerase chain reaction (RT- PCR).

RESULTS

Mutation of FVL gene was detected in 5.9% women of group A (2 of 34) compared with 2.8% women (1 of 36) of control group (P = 0.6). Mutation of MTHFR gene was found in 35.3% (12 cases) as compared with 50% (18 cases) of control (35.3% versus 50%; P = 0.23). Regarding Prothrombin, only control group had 5.6% mutation (P = 0.49). No significant differences were detected in the incidences of FVL, Prothrombin and MTHFR in the study group A compared with the control group B.

CONCLUSION

The obtained results suggest that thrombophilia does not have a significant effect in ART failures.

Fertility, Infertility and Thrombophilia

Hypercoagulation has been reported in some studies to be associated with reproductive failures, such as unexplained infertility, IVF implantation failure and recurrent fetal losses. Many pregnancy-related disorders have been interpreted as consequences of impaired microvascular function and might be viewed as a mild form of venous thromboembolic disease. In the absence of clinical guidelines, there is a need for an evidence base regarding thrombophilic screening and antithrombotic therapy in cases of reproductive failure. This article will focus on the controversial effect of congenital and acquired thrombophilia on human fertility, and will review the English literature for relevant studies identified by searching PubMed® results between January 1966–November 2010 using the key words: ‘thrombophilia‘, ‘fertility’ and ‘infertility‘.

Low-Molecular-Weight Heparin in Women with Repeated Implantation Failure

Implantation failure is common in assisted reproduction techniques (ART). The role of low-molecular-weight heparin (LMWH) is a matter of debate as a potential factor to improve implantation. Aim: To evaluate the pregnancy rate in patients with or without heparin administration. Materials & methods: We performed a retrospective observational analysis of patients with at least two IVF/intracytoplasmic sperm injection cycles with implantation failure, screened for inherited thrombophilia and submitted to further ART cycles with or without administration of LMWH. A total of 265 patients fulfilled the enrollment criteria. Of these 149 (56%) were primary infertile and 116 (44%) were secondary infertile. Their mean age was 36.3 ± 3.6 years. We analyzed basal FSH, smoking habit, gene variants for inherited thrombophilia (i.e., MTHFR C677T, prothrombin G202A10G and factor V Leiden). The patients underwent 569 new ART cycles: 512 (90%) without and 57 (10%) with LMWH. Results: In total 105 clinical pregnancies were observed in 569 cycles (18.8%). The pregnancy rate was 17.19% (88/512) in patients not treated with LMWH and 29.52% (17/57) in the LMWH-treated group (p = 0.006). In women over 36 years of age the pregnancy rate was 15.53% (50/322) in nontreated versus 35.71% (10/28) in treated cycles (p = 0.007), while no difference was found in younger women. No statistical difference was found between the presence of inherited thrombophilia and pregnancy rate in treated and untreated cycles. Discussion: significantly higher pregnancy rate in patients with previous ART implantation failures was observed with LMWH. Our results confirm no relation among inherited thrombophilia and pregnancy rate in patients with previous IVF implantation failures. These findings should be confirmed by randomized controlled trials before use of LMWH for ART cycles is recommended.