The ‘ART’ of thrombosis: a review of arterial and venous thrombosis in assisted reproductive technology

Venous thromboembolism associated with medically assisted reproduction (MAR): British fertility society policy and practice guidance for assessment and prevention

The association between Medically Assisted Reproduction (MAR) and thromboembolic complications has been reported widely in multiple published studies. Although venous thromboembolism (VTE) is not thought to be a common complication of MAR, it is associated with high morbidity and is often preventable. Since VTE usually occurs after completion of MAR treatment and is often managed outside of the treating fertility unit, these complications are likely to be underreported and there may be limited awareness of the risks among clinicians. As we continue to see a rise in the total number of MAR treatment cycles, particularly in women over 40 years of age, along with a steady increase in the number of fertility preservation cycles for both medical and social indications, it is likely that we will see an increase in absolute numbers of VTE complications. Currently, there is a lack of management guidance and reporting of VTE events associated with assisted conception treatment. The aim of this guidance is to provide clinicians with information on VTE risk factors, guidance on assessing VTE risk and the best practice recommendations on risk reducing strategies for individuals at risk of VTE undergoing ovarian stimulation and embryo transfer cycles.

COVID-19: A Challenge to the Safety of Assisted Reproduction

There is an increased risk of becoming pregnant through fertility treatments using assisted reproductive technology (ART) during the COVID-19 pandemic. The aim of this review is to gather comprehensive data from the existing literature on the potential risks of fertility management during the pandemic period, and outline strategies to mitigate them, with a focus on the hormonal and surgical procedures of ART. A comprehensive search of the scientific literature on COVID-19 in relation to fertility was conducted in the PubMed database using the keywords "coronavirus," "COVID-19," "SARS-CoV-2" and "pregnancy," "fertility," "urogenital system," "vertical transmission," "assisted human reproduction," "controlled ovarian stimulation," "oocyte retrieval," "in vitro fertilization," "hormones," "surgical procedures," "embryos," "oocytes," "sperm," "semen," "ovary," "testis," "ACE-2 receptor," "immunology," "cytokine storm," and "coagulation," from January 2020-July 2022. Published data on pregnancy and COVID-19, and the interaction of the urogenital system and SARS-CoV-2 is reported. The immunologic and prothrombotic profiles of patients with COVID-19, and their increased risks from controlled ovarian stimulation (COS) and ART surgeries, and how these procedures could facilitate COVID-19 and/or contribute to the severity of the disease by enhancing the cytokine storm are summarized. Strategies to prevent complications during COS that could increase the risks of the disease in pre-symptomatic patients are considered. The impact of SARS-CoV-2 on pre-symptomatic infertile patients presents a challenge to find ways to avoid the increased hormonal, immunologic, and prothrombotic risks presented by the use of COS in ART protocols during the COVID-19 outbreak. Safe ART procedures and recommendations are highlighted.

Venous Thromboembolism Associated with Assisted Reproductive Technology: A Systematic Review and Meta-analysis

BACKGROUND

 Hormonal exposure leads to an increased risk of venous thromboembolism (VTE) but the risk of VTE associated with assisted reproductive technology (ART) is not clearly determined.

METHODS

 We searched in PubMed, EMBASE, Web of Science, and the Cochrane Library databases and identified all relevant articles published up to February 1, 2021. The primary objective was to determine the frequency of VTE associated with ART. Secondary objectives were to determine (1) the risk of VTE associated with ART as compared to pregnancy without ART; (2) the risk of VTE associated with ovarian hyperstimulation syndrome (OHSS); and (3) to determine potential risk factors of VTE related to ART.

RESULTS

 Fourteen studies were included. The overall frequency of VTE associated with ART was 0.23% (95% confidence interval [CI]: 0.07-0.46). Women undergoing ART had a two- to threefold increased risk of VTE as compared to spontaneous pregnancy (relative risk [RR]: 2.66; 95% CI: 1.60-4.43). The overall frequency of VTE specifically related to OHSS was <0.001%. The risk of VTE after ART complicated by OHSS, as compared to ART without OHSS, was higher but not statistically significant (RR: 14.83; 95% CI: 0.86-255.62). Risk factors of VTE associated with ART were in vitro fertilization procedure (RR, odds ratio [OR], and hazard ratio varying from 1.77, 95% CI: 1.41-2.23 to 4.99, 95% CI: 1.24-20.05), hyperhomocysteinemia (OR: 15.2; 95% CI: 2.0-115.0), polycystic ovarian syndrome (PCOS) (RR: 4.8; 95% CI: 1.7-13.4), successful ART leading to pregnancy (OR: 13.94; 95% CI: 1.41-137.45).

CONCLUSION

 Further large prospective studies on risk factors of VTE in women undergoing ART are needed in order to optimize thromboprophylaxis in this context.

The ART of Thromboprophylaxis in the Prevention of Gestational Venous Thromboembolism

Assisted reproductive techniques (ART) allow infertile couples to conceive. Use of hormones to obtain a controlled ovarian stimulation and an adequate growth of the endometrium preparatory for embryo implantation are not riskless. Among others, thrombotic events can occur during the ovulation induction or pregnancy following ART. As the number of women approaching ART to conceive is steadily increasing, the issue of thrombotic risk in this setting is relevant. Data on the weight of each risk factor and on potential benefit of thromboprophylaxis are largely lacking. In this review, we discuss risk of venous thromboembolism during pregnancy following ART, with a focus on general (i.e.: age, body mass index, thrombophilia, bed rest, transfusions) and ART-specific (i.e., polycystic ovarian syndrome, ovarian hyperstimulation syndrome) risk factors. We also attempt to provide some suggestions to guide clinical practice, based on available data and studies performed outside ART.

Overview of hospitalizations in women undergoing oocyte retrieval for ART in the French national health data system

STUDY QUESTION

What is the incidence rate of complications in women undergoing ART procedures compared to the period prior to their first oocyte retrieval?

SUMMARY ANSWER

The study shows a significant increase in the post-ART incidence rate of some complications but a low overall rate of occurrence relative to the total number of oocyte retrievals.

WHAT IS KNOWN ALREADY

ART, widely used in Europe, accounts for 3.3% of births in France. The various studies of ART complications are fairly reassuring, showing relatively low overall complication rates but only few studies have used exhaustive national registers.

STUDY DESIGN, SIZE, DURATION

The cohort for this study was identified from the comprehensive French national hospital-discharge database and includes women under 50 years with a first oocyte retrieval (T0) in 2012-2017, classified in three population subgroups according to the indication for oocyte retrieval: infertility (IF), oocyte donation (OD), and fertility preservation (FP). This study includes 156 916 women whose first oocyte retrieval occurred in 2012-2017 and 542 775 hospitalizations in 2010-2019 (excluding first retrieval).

PARTICIPANTS/MATERIALS, SETTING, METHODS

Hospitalizations for complications or others events (oocyte retrieval, delivery, pregnancy loss, and death in the hospital) during the 2 years before (control period) and after their first oocyte retrieval (post-oocyte retrieval period) were compared and expressed per 10 000 person-months (pm).

MAIN RESULTS AND THE ROLE OF CHANCE

In the IF subgroup, incidence rates were significantly higher after (vs before) retrieval for hospitalized ovarian hyperstimulation syndrome (OHSS) (162 vs 6/10 000 pm), adnexal torsion (14 vs 3), venous thrombosis (8 vs 1), arterial thrombosis (3 vs 1), trauma (2 vs 1), and significantly lower for infections (61 vs 87). The higher incidences of OHSS, adnexal torsion and venous thrombosis could only partially be explained by the occurrence of pregnancy.In the FP subgroup, incidence increased significantly after (vs before) retrieval for hospitalized OHSS (55 vs 0), venous thrombosis (59 vs 4), and infections (176 vs 56). For the OD subgroup, hospitalized OHSS (116 vs 0) and bleeding (24 vs 0) were significantly higher after (vs before) retrieval.

LIMITATIONS, REASONS FOR CAUTION

The French national health data system, despite all its advantages, present some limitations such as the risk of coding errors. The unavailability of some personal information and the absence of consideration of risk factors prevented us from adjusting the risk. Finally, only complications resulting in hospitalization were analyzed which probably leads to their underestimation.

WIDER IMPLICATIONS OF THE FINDINGS

The use of medico-administrative bases will be a valuable tool in public health and will furnish a better overview of the complications. Further studies are needed to complete this analysis. Adding information on drugs would help to better define T0 and less severe complications.

STUDY FUNDING/COMPETING INTEREST(S)

N/A.

TRIAL REGISTRATION NUMBER

N/A.

Thrombophilia, Inflammation, and Recurrent Pregnancy Loss: A Case-Based Review

Recurrent pregnancy loss (RPL) is defined as the loss of two or more pregnancies and is often multifactorial with the majority of miscarriages being due to aneuploidy and anatomic or physiological abnormalities. However, inherited or acquired thrombophilias have also been associated with RPL, albeit inconsistently. While inherited thrombophilias, such as factor V Leiden and prothrombin gene mutation, are relatively prevalent in women with RPL compared with the general population, a causal link has yet to be definitively established. Recently, systemic inflammation, as measured by high-sensitivity C-reactive protein, has also been hypothesized to play a role in infertility. Based on limited prospective trial data, antithrombotic therapy and antiplatelet agents have been proposed as possible tools for the prevention of RPL. Because of the multifactorial nature of RPL and infertility, various clinicians, as obstetricians and gynecologists, endocrinologists, hematologists, or vascular medicine specialists, may be requested to counsel these women. This, together with evidence gaps, frequently leads to distinctly different diagnostic and therapeutic recommendations, especially regarding thrombophilia testing and treatment. Using four case vignettes in this review, we critically appraise the literature and highlight how two clinicians from different subspecialties approach the relationship between RPL, inflammation, and thrombophilia.

Relationship Between Estradiol and Hemostasis Determined Through Thromboelastography Profile in Controlled Ovarian Stimulation Cycles

Purpose

We aimed to analyze the relationship between estradiol level and thromboelastography profile.

Patients and Methods

This prospective study with comparative analysis was performed on nineteen samples undergoing an IVF procedure in two fertility clinics in Bandung city. Blood samples taken on the second and twelfth days of the IVF cycle.

Results

There were significant differences in the value of estradiol, fibrin formation time (α), and coagulation index (CI) (p<0.05). Correlation tests showed no relationship and no significant correlation between an increased level of estradiol and coagulation index (CI) (r _s=0.054; p=0.827) and between an increased level of estradiol and fibrinolysis time (LY30) (r _s=-0.151; p=0.536). A moderate significant relationship was observed between age and coagulation index (CI) (r _s=-0.430; p=0.033) and between age and maximum amplitude (MA) (r _s=-0.494; p=0.032).

Conclusion

Supraphysiological estradiol levels in controlled ovarian stimulation cycles affect the coagulation index and change mainly the fibrin formation time.

Involvement of single nucleotide polymorphisms in ovarian poor response

PURPOSE

Unpredictability in acquiring an adequate number of high-quality oocytes following ovarian stimulation is one of the major complications in controlled ovarian hyperstimulation (COH). Genetic predispositions of variations could alter the immunological profiles and consequently be implicated in the variability of ovarian response to the stimulation.

DESIGN

Uncovering the influence of variations in AMHR2, LHCGR, MTHFR, PGR, and SERPINE1 genes with ovarian response to gonadotrophin stimulation in COH of infertile women.

METHODS

Blood samples of the women with a good ovarian response (GOR) or with a poor ovarian response (POR) were collected. Genomic DNA was extracted, and gene variations were genotyped by TaqMan SNP Genotyping Assays using primer-probe sets or real-time PCR Kit.

RESULTS

Except for PGR (rs10895068), allele distributions demonstrate that the majority of POR patients carried minor alleles of AMHR2 (rs2002555, G-allele), LHCGR (rs2293275, G-allele), MTHFR (rs1801131, C-allele, and rs1801133, T-allele), and SERPINE1 (rs1799889, 4G allele) genes compared to the GOR. Similarly, genotypes with a minor allele in AMHR2, LHCGR, MTHFR, and SERPINE1 genes had a higher prevalence among POR patients with the polymorphic genotypes. However, further genotype stratification indicated that the minor alleles of these genes are not associated with poor response. Multivariate logistic analysis of clinical-demographic factors and polymorphic genotypes demonstrated a correlation between FSH levels and polymorphic genotypes of SERPINE1 in poor response status.

CONCLUSIONS

Despite a higher prevalence of AMHR2, LHCGR, MTHFR, and SERPINE1 variations in the patients with poor ovarian response, it seems that these variations are not associated with the ovarian response.

Fibrin clot properties among women with endometriosis and the impact of ovarian stimulation

RESEARCH QUESTION

Is there a difference in fibrin clot phenotype in women with endometriosis before and after ovarian stimulation?

DESIGN

Prospective study including 73 infertile women in two age-matched groups: (i) with confirmed endometriosis (n = 29); (ii) without endometriosis (n = 44). Assessments of plasma fibrin clot permeability (K_s), efficiency of fibrinolysis using clot lysis time (CLT), along with thrombin generation (prothrombin fragments 1+2 [F1+2] and endogenous thrombin potential [ETP]) and fibrinolysis inhibitors were performed together with clinical pregnancy rate.

RESULTS

Endometriosis was associated with increased thrombin generation, reflected by both higher F1+2 (+96.1%, P = 0.005) and ETP (+14.2%, P = 0.014) along with unfavourably altered fibrin clot properties represented by lower K_s (-31%, P < 0.001) and prolonged CLT (+13.5%, P = 0.02), compared with the non-endometriosis group. Moreover, women with endometriosis had higher plasminogen activator inhibitor-1 (PAI-1; +272%, P = 0.004) concentrations and alpha-2-antiplasmin activity (+39.9%, P < 0.001) in contrast to the other group. Ovarian stimulation led to reduction in F1+2 (-48.1%, P < 0.001), improvement of fibrin clot phenotype reflected by higher K_s (+25.9%, P < 0.001) and shortened CLT (-11.9%, P < 0.001), along with lower PAI-1 (-54%, P = 0.016) compared with the baseline in women with endometriosis.

CONCLUSIONS

Endometriosis is associated with the prothrombotic fibrin clot phenotype and increased thrombin generation. Ovarian stimulation favourably alters fibrin clot properties and leads to comparable pregnancy outcomes to those in women without endometriosis.

The freeze-all strategy after IVF: which indications?

The freeze-all strategy is gaining popularity worldwide as an alternative to the conventional fresh embryo transfer. It consists of cryopreservation of the entire embryo cohort and the embryo transfer in a subsequent cycle that takes place separately from ovarian stimulation. The freeze-all strategy was initially a 'rescue' strategy for women at high risk of ovarian hyperstimulation syndrome; however, this approach has been extended to other indications as a scheduled strategy to improve implantation rates. This assumes that ovarian stimulation can alter endometrial receptivity in fresh cycles owing to the effect of supraphysiological levels of steroids on endometrial maturation. The procedure, however, has not been associated with increased live birth rates in all infertile couples, and concerns have been raised about the occurrence of several adverse perinatal outcomes. It is, therefore, crucial to identify in which subgroups of patients a freeze-all strategy could be beneficial. The aim of this review is to summarize current scientific research in this field to highlight potential indications for this strategy and to guide clinicians in their daily practice.

Lipid Metabolic Disorders and Ovarian Hyperstimulation Syndrome: A Retrospective Analysis

Objectives

To evaluate the effect of dyslipidemia on the incidence of moderate and severe Ovarian hyperstimulation syndrome (OHSS) in the duration of assisted reproduction technique (ART).

Methods

The study included 233 moderate and severe OHSS patients who received hospitalization after in-vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI) cycles to avoid severe complications. They were divided into dyslipidemia group and normal lipid metabolism group to evaluate whether dyslipidemia contributes to the development of severe OHSS. Subgroup analysis was set to avoid deviation including the freeze-all group and fresh embryo transfer (ET) group according to whether the eligible women chose fresh embryo transfer immediately after their IVF or ICSI cycles. The main outcome measures included the incidence of moderate OHSS and severe OHSS, total gonadotropin dose, number of oocytes retrieved, age and body mass index (BMI). In the ET groups, the rate of pregnancy is also included for analysis.

Results

In the freeze-all group, lipid metabolism was ultimately identified as the factor affecting the morbidity of severe OHSS and the ones with dyslipidemia were more likely to develop to severe OHSS (P < 0.05), while the incidence of severe OHSS among the ET groups had no statistical significance (P > 0.05).

Conclusion

The findings of this study suggested that dyslipidemia might contribute to the development of OHSS, especially for those patients who chose the cryopreservation of all embryos. It is essential to consider the risk of OHSS in patients with dyslipidemia although they required cryopreservation of all embryos.

Venous thromboembolism in women: new challenges for an old disease

In countries that have controlled classic causes of maternal death, such as eclampsia and hemorrhage, venous thromboembolism (VTE) has become the major concern. Prevention of VTE during pregnancy and postpartum by applying guidelines and implementing pharmacoprophylaxis is still the best strategy to reduce occurrence of this complication. Hormonal contraceptives and hormone replacement therapy also increase the risk of VTE, but women cannot be deprived of their benefits, which increase their freedom at childbearing age and reduce their symptoms at menopause. Both indiscriminate use and unmotivated prohibition are inappropriate. Contraceptive and hormone replacement methods should be chosen with care, evaluating the patients’ contraindications, eligibility criteria, and autonomy. This article presents a nonsystematic review of recent literature with the aim of evaluating and summarizing the associations between VTE and clinical situations peculiar to women.

Assisted reproduction and thromboembolic risk in the COVID-19 pandemic

The COVID-19 pandemic has significantly increased mortality in many countries, with the number of infected cases increasing exponentially worldwide. One of the main determining factors of the poor prognosis in these patients is the development of coagulopathy. Moreover, it is well known that assisted reproductive technology procedures confer a risk of thromboembolic complications. This commentary analyses specific aspects coexisting between the thrombotic risk described during virus infection and that reported in the context of assisted reproduction treatments. Based on known pathophysiological aspects of virus infection and of ovarian stimulation, there are common elements that deserve to be taken into account. In the present context, any risk of hyperstimulation should be avoided. Gonadotrophin-releasing hormone agonist triggering should be mandatory in high-responder patients and/or those with COVID-19 infection. In both cases, the cycle should be segmented. A proposal is made for the use of prophylactic low molecular weight heparin not only in those cases in which oocyte retrieval has been performed, but also in those in which cancellation has been decided. In addition, endometrial preparation for frozen-thawed embryo transfers should use the transdermal route in order to minimize the higher thrombotic risk associated with the oral route.

2020 American College of Rheumatology Guideline for the Management of Reproductive Health in Rheumatic and Musculoskeletal Diseases

OBJECTIVE

To develop an evidence-based guideline on contraception, assisted reproductive technologies (ART), fertility preservation with gonadotoxic therapy, use of menopausal hormone replacement therapy (HRT), pregnancy assessment and management, and medication use in patients with rheumatic and musculoskeletal disease (RMD).

METHODS

We conducted a systematic review of evidence relating to contraception, ART, fertility preservation, HRT, pregnancy and lactation, and medication use in RMD populations, using Grading of Recommendations Assessment, Development and Evaluation methodology to rate the quality of evidence and a group consensus process to determine final recommendations and grade their strength (conditional or strong). Good practice statements were agreed upon when indirect evidence was sufficiently compelling that a formal vote was unnecessary.

RESULTS

This American College of Rheumatology guideline provides 12 ungraded good practice statements and 131 graded recommendations for reproductive health care in RMD patients. These recommendations are intended to guide care for all patients with RMD, except where indicated as being specific for patients with systemic lupus erythematosus, those positive for antiphospholipid antibody, and/or those positive for anti-Ro/SSA and/or anti-La/SSB antibodies. Recommendations and good practice statements support several guiding principles: use of safe and effective contraception to prevent unplanned pregnancy, pre-pregnancy counseling to encourage conception during periods of disease quiescence and while receiving pregnancy-compatible medications, and ongoing physician-patient discussion with obstetrics/gynecology collaboration for all reproductive health issues, given the overall low level of available evidence that relates specifically to RMD.

CONCLUSION

This guideline provides evidence-based recommendations developed and reviewed by panels of experts and RMD patients. Many recommendations are conditional, reflecting a lack of data or low-level data. We intend that this guideline be used to inform a shared decision-making process between patients and their physicians on issues related to reproductive health that incorporates patients' values, preferences, and comorbidities.

Low molecular weight heparins use in pregnancy: a practice survey from Greece and a review of the literature

Background

Use of LMWH in pregnancy is not only limited to VTE management, but it extends, to the management of vascular gestational complications and the optimization of IVF pregnancies despite the lack of concrete scientific evidence. In this context, we conducted the present study aiming to gain insights regarding the use of LMWH during pregnancy and puerperium. We recorded indication for use, diagnostic work-up as well as the safety and efficacy of the treatment, trying to elucidate the clinical practice in our country.

Methods

We analyzed data regarding 818 pregnant women received LMWH during 2010-2015.Our cohort had a median age of 33.9 years and a BMI of 23.6.There were 4 groups: those with a history of VTE [Group-A: 76], those with pregnancy complications [Group-B: 445], those undergoing IVF [Group-C: 132] and those carrying prothrombotic tendency (thrombophilia, family history of VTE, other) [Group-D: 165]. Mean duration of LMWH administration was 8.6 ± 1.5 months. Out of the total number, 440 received LMWH in fixed prophylactic dose, 272 in higher prophylactic-weight adjusted dose and 106 in therapeutic dose. Moreover, 152 women received in addition low-dose acetylsalicylic acid (ASA). 93.8% of pregnancies were single and 6.2% were multiple ones. Live births occurred in 98.7% of pregnancies.

Results

Anticoagulation was efficacious and well tolerated. Seventeen VTE events were recorded; 7 of them antepartum and 10 postpartum. No major bleeding events were observed while 13 clinical relevant non-major bleeding events were recorded. Regarding gestational vascular complications, 28 IUGR events were recorded, as well as 48 cases of preterm labor of which 12 were concomitant with IUGR (25%). Six early pregnancy losses were recorded; there were 3 fetal deaths and 3 cases of pre-eclampsia/eclampsia.

Conclusions

LMWHs are used extensively during pregnancy and puerperium in Greece for VTE treatment and prophylaxis and for a variety of other indications as well. Although the drug has been shown to be both safe and efficacious, its use for some indications has no proven scientific evidence. In order to clearly define the role of LMWHs in pregnancy, beyond thromboprophylaxis, large prospective studies are required, which could be based on the conclusions of this study.

Assisted reproductive technologies for women with rheumatic AID

Assisted reproductive technology (ART) procedures are safe for women with rheumatic autoimmune diseases (rAID) when illness is inactive. Medications incompatible with pregnancy should be replaced with alternative pregnancy-compatible medications months before planned ART procedures to allow time to verify the substitute medication's efficacy and tolerability. Medications compatible with pregnancy should be continued, as should anticoagulation (warfarin changed to low-molecular-weight heparin) before pregnancy begins. Protocols that provide details for specific medications are available. All patients with rAID should be screened for diagnosis-relevant organ system damage, and those intending to carry their own pregnancies must be tested for aPL and anti-Ro/La autoantibodies. Patients with organ damage and/or positive tests for aPL and anti-Ro/La should be counseled about fetal and maternal risks, including implications to the child and family of maternal disability or death. Sperm donors with rAID may need to discontinue medications. REI and physicians treating patients with rAID (usually rheumatologists) must work together to plan and accomplish ART.

The implication of single-nucleotide polymorphisms in ovarian hyperstimulation syndrome

Ovarian hyperstimulation syndrome (OHSS) is an undesirable complication in the course of ovarian stimulation. This kind of stimulation is aimed at acquiring a sufficient number of high-quality oocytes in in vitro fertilization (IVF). Whereas the predisposition to OHSS could be impacted by genetic polymorphisms in susceptible genes, the present study has been jointly conducted with an Iranian cohort to scrutinize its relevant implication. Genomic DNA was extracted from blood samples of patients with a normal ovarian response (NOR) or with OHSS. Samples were analyzed to detect polymorphisms MTHFR rs1801131, MTHFR rs1801133, AMHR2 rs2002555, LHCGR rs2293275, PGR rs10895068, and SERPINE1 rs1799889. Variations of MTHFR, AMHR2, LHCGR, and PGR genes were significantly associated with the developing OHSS. After correction for multiple analysis, this difference was not evident for PGR genotypes. The polymorphic alleles of MTHFR (rs1801131 C-allele and rs1801133 T-allele), AMHR2 (rs2002555 G-allele), and LHCGR (rs2293275 G-allele) were significantly more prevalent among patients with OHSS compared to those in the NOR group. In contrast, the minor allele of PGR single-nucleotide polymorphism (SNP) (rs10895068, A-allele) was more prominent among patients with a NOR than those with OHSS. No significant difference was observed in genotypes or alleles of SERPINE1 rs1799889. The observations indicated that the minor alleles of MTHFR, AMHR2, and LHCGR genes could be considered an independent risk factor in susceptibility to OHSS. Nevertheless, polymorphic allele in the PGR rs10895068 SNP contributes to preventing OHSS occurrence. Therefore, it can be argued that these genes have a significant impact on OHSS.

Ovarian Hyperstimulation Syndrome and Myocardial Infarction: A Systematic Review

BACKGROUND

Ovarian hyperstimulation syndrome (OHSS) is a rare but serious complication of ovarian stimulation occurring during assisted reproduction technologies (ART). It is characterized by increased vascular permeability and hypercoagulable states resulting in strokes and peripheral ischemia. Acute myocardial infarction and cardiac thrombosis, however, have been rarely reported complications of OHSS.

METHODS

A literature search was performed for reports on myocardial infarction and cardiac thrombosis associated with ovarian stimulation with a summary of their clinical characteristics.

RESULTS

A total of twelve published cases were reviewed with 5 out of 12 (41.67%) of the reported cases were 35 years of age or older. Myocardial infarction was reported in 10 out of the 12 cases (83.3%). Two of the cases were pregnant at presentation (16.67%). The mean duration between starting ovarian stimulation medications and clinical presentation was 23 days. Chest pain was the most common presenting symptom (66.67%), 2 cases presented with stroke (16.67%) and 2 cases presented with abdominal distention (16.67%). A total of 8 patients underwent coronary angiography with 2 of these cases were treated with percutaneous coronary intervention. No mortality reported in any of the twelve cases.

CONCLUSION

Women of a relatively younger age undergoing ovarian stimulation may be at risk for developing myocardial infarction and cardiac thrombosis. Once thrombosis is suspected, initiating appropriate therapy in a timely manner is crucial.

Oral versus transdermal oestrogen delivery for endometrial preparation before embryo transfer: a prospective, comparative, randomized clinical trial

RESEARCH QUESTION

To determine whether the transdermal route is equal or superior to the oral route, when preparing the endometrium with oestrogens for embryo transfer.

DESIGN

Prospective, randomized controlled trial; 140 patients randomized; the pills group followed a protocol with oestradiol valerate pills and the patches group followed a protocol with oestradiol hemihydrate patches. The primary variable was endometrial thickness on day 10 ± 1 of treatment. Secondary variables were endometrial thickness on day 15 ± 1 of treatment, patient satisfaction, plasma levels of oestradiol, rates of pregnancy, miscarriage and delivery. Endometrial thickness was measured on day 10 ± 1 of the cycle, if the lining was 7 mm or less in thickness, another measurement was made on day 15 ± 1. Blood oestradiol levels were analysed on the day the endometrial lining was greater than 7 mm (day 10 ± 1 or day 15 ± 1). Patients completed a survey to evaluate comfort and side-effects.

RESULTS

The patches group achieved significantly thicker endometrium by the first check-up on day 10 ± 1 (7.6 mm versus 7.0 mm; P = 0.026), with lower blood levels of oestradiol (159.2 pg/ml versus 237.1 pg/ml; P < 0.001) when the endometrial thickness was over 7mm. The pills group considered the treatment more comfortable, with less side-effects. No significant differences in the rates of pregnancy, miscarriage or live birth were found.

CONCLUSIONS

Transdermal oestrogen treatment allows patients to reach a higher endometrial thickness after 10 days of treatment, with lower plasma levels of oestradiol, although it is not tolerated as well.

Does low-dose aspirin improve pregnancy rate in women undergoing frozen-thawed embryo transfer cycle? A pilot double-blind, randomized placebo-controlled trial

AIM

To evaluate the effect of adjuvant low-dose aspirin therapy on clinical pregnancy rate and uterine perfusion in women undergoing frozen-thawed embryo transfer (FET) cycles.

METHODS

This study was performed as a pilot randomized, double-blind placebo-controlled trial, from May 2012 to February 2015. Overall, 60 available eligible women who were candidates for FET were randomly assigned to two groups receiving either 100 mg oral aspirin (n =30) or placebo (n =30). The primary outcome measure was clinical pregnancy rate. Secondary outcome measures were pulsatility index (PI), resistance index (RI), implantation rate, live birth rate and miscarriage rate.

RESULTS

There was no significant difference in endometrial thickness, PI and RI. However, the study group had higher rates of clinical pregnancy, implantation, live birth (P = 0.042, P = 0.031 and P = 0.007, respectively) and lower rate of miscarriage (P = 0.020) as compared to the control group. Twin birth rate was comparable between the two groups.

CONCLUSION

Our pilot study demonstrated that administration of low-dose aspirin in FET cycles results in better pregnancy, implantation and live birth rates without changing the uterine hemodynamics or endometrial thickness. However, further randomized clinical studies in larger populations are needed to confirm these findings.

Family Planning and Pregnancy Management in Adults with Congenital Heart Disease

With advances in congenital heart disease management, there are an increasing number of women reaching reproductive age. Pregnancy results in a surge of hormones and increased demands on both the cardiovascular (CV) and respiratory systems. Depending on the heart defect and the treatments the mother has undergone, these hemodynamic changes can result in an increased risk of maternal CV events and an increased risk of fetal morbidity and mortality. Thus, it is important to have a comprehensive approach to adult congenital heart disease patients involving pre-pregnancy planning in addition to diligent peri- and post-partum care.

Is thromboprophylaxis cost effective in ovarian hyperstimulation syndrome: A systematic review and cost analysis

BACKGROUND

The majority of serious thromboembolic events occurring in assisted reproductive technologies (ART) are in women with ovarian hyperstimulation syndrome (OHSS).

OBJECTIVES

The purpose of this study was to present a thorough review and cost analysis regarding the use of venous thromboembolism (VTE) prophylaxis in OHSS to inform clinical management.

DATA SOURCES

Databases used were Pubmed and Embase, in addition to checking reference lists of retrieved articles (inception to November 2017).

METHODS

The systematic search strategy identified 365 titles and abstracts. Articles included in the qualitative synthesis had identified venous thrombosis incidence rates or ratios. A separate search for the cost model was conducted recognizing all associated complications of VTE. The decision tree was modeled to best fit the patient population and a sensitivity analysis was performed over a range of variables.

RESULTS

The cost of VTE event per OHSS patient not on prophylaxis was €5940 (range €3405 to €38,727), versus €4134 (€2705 to €23,192) per event per patient on prophylaxis, amounting to a saving of (€19 to €23,192) per VTE per patient. Sensitivity analysis found VTE prophyaxis to be cost effective if the incidence of VTE in the OHSS population was greater than 2.79%. Prophylactic therapy was cost effective through 16 weeks of treatment.

LIMITATIONS

OHSS is infrequent and hence, the incidence of VTE in patients with OHSS is low; therefore, the data used to inform the incidence of VTE in OHSS in the model carry some uncertainty. Further, low molecular weight heparin (LMWH) has side effects therefore individualization of care must be considered.

CONCLUSIONS

With the increasing incidence of infertility and requirement for ART, thromboembolism in OHSS poses a major health threat for patients. VTE prophylaxis using enoxaparin was cost effective in patients with severe OHSS over a wide range of costs and incidences. Prophylaxis was also cost effective through the completion of the first trimester of pregnancy.

Ovarian hyperstimulation syndrome as a rare cause of acute bilateral limb and renal ischemia

Ovarian hyperstimulation syndrome (OHS) is a rare and potentially fatal condition, particularly when it is associated with arterial thromboembolic events. We present a case of acute ischemia of both lower limbs and left kidney due to OHS. The clinical presentation included voluminous ascites, pleural effusion, and significant ovarian enlargement. Subsequently, bilateral severe acute limb ischemia and left kidney segmental infarction were established. Surgical thromboembolectomy and muscle débridement of the lower limbs were necessary, and the patient recovered with partial limitations. A high index of suspicion and timely treatment are essential to minimize consequences of arterial thrombosis associated with OHS.

Assisted Reproductive Techniques in a Patient with History of Venous Thromboembolism: A Case Report and Review of Literature

We report a patient with a history of venous thrombosis following oral contraceptive pills who was planned for in vitro fertilization (IVF)-intracytoplasmic sperm injection for male factor infertility. This article discusses the mechanisms for predisposition to thrombosis during assisted reproduction in patients at high risk. Assessment of risk before commencement of treatment, use of mild stimulation, antagonist protocol, avoiding ovarian hyperstimulation, use of gonadotropin-releasing hormone agonist trigger and avoiding exposure to human chorionic gonadotropin, frozen embryo transfer in a natural cycle, single embryo transfer, avoiding multiple pregnancy, and use of prophylactic or therapeutic anticoagulation are the various risk-reduction strategies that must be adopted during IVF treatment to reduce the risk of thrombosis to that of natural conception.

An Unusual Cause of Stroke: Internal Carotid Artery Occlusion as a Complication of Ovarian Hyperstimulation Syndrome

Ovarian hyperstimulation syndrome (OHSS) is a rare iatrogenic complication of ovarian stimulation. Thromboembolic events are the most feared complication of OHSS. Most of the thrombotic events (75%) are of the venous origin. Stroke represents a rare but life-threatening complication of severe OHSS. A 29-year old woman was admitted to our emergency room, with left sided weakness, difficulty in breathing and nausea. The patient was given the diagnosis of OHSS and right middle cerebral artery infarction. Here we emphasise that the development of ovulation induction is a newly recognised cause of cerebral stroke in an otherwise healthy woman.

Deferred Frozen Embryo Transfer: What Benefits can be Expected from this Strategy in Patients with and without Endometriosis?

Progress with cryopreservation techniques have enabled development of the deferred frozen-thawed embryo transfer (DET) strategy as an alternative to relying on fresh embryo transfers.

With DET, the entire embryo cohort is cryopreserved, and embryo transfer is then performed in a subsequent cycle that takes place separately from the controlled ovarian stimulation (COS).

Initially developed to limit the risk of ovarian hyperstimulation syndrome that occurs with high responders, this strategy has been applied extensively with other populations in an effort to improve implantation rates. The assumption is that COS, which is essential for in vitro fertilization/intra cytoplasmic sperm injection (IVF/ICSI) procedures to obtain a multi-follicular development, could have a detrimental impact on the endometrium as a result of greatly elevated levels of steroids. It is currently not clear whether the DET strategy can be generally applied to all women requiring an IVF/ICSI procedure.

The objectives of this literature review regarding DET, were hence: (i) to present the scientific background that contributed to extensive adoption of this technique, (ii) to detail the pregnancy outcomes and potential obstetric and neonatal consequences, (iii) to report on its ability to prevent risks induced by COS, and (iv) to propose indications for the DET strategy in clinical practice.

The Clinical Characteristics of Acute Cerebrovascular Accidents Resulting from Ovarian Hyperstimulation Syndrome

BACKGROUND AND PURPOSE

Ovarian hyperstimulation syndrome (OHSS) is a serious complication that occurs after the ovarian-induction treatment. Acute cerebrovascular accident is one of the most dangerous manifestations of the syndrome. However, the characteristics of stroke resulting from OHSS have so far not been well summarised in any study.

METHODS

We reported 2 cases of acute cerebrovascular accidents secondary to OHSS. And then we performed a literature search for reports on this type of stroke, and summarised their characteristics.

RESULTS

Thirty-six published cases of this type of stroke were reviewed. Thirty two out of 36 (88.9%) of the women were 35 years old or younger. Stroke in 28 out of 36 (77.8%) of these cases was caused by arterial thrombosis. In 17 out of 28 cases, the involved cerebral vascular branches were mainly middle cerebral artery (MCA) and internal carotid artery (ICA). The acute cerebrovascular accidents happened 7 and 9.25 days after embryo transplantation or 8 and 8.33 days after last human chorionic gonadotropin treatment respectively. The prognosis of patients was relatively good after anticoagulation and some supportive treatments.

CONCLUSION

The MCA and ICA are easily involved in stroke resulting from OHSS. The young age may be a risk factor for developing stroke secondary to OHSS. Once thromboembolism develops, administering appropriate therapy is crucial.

Freezing oocytes or embryos after controlled ovarian hyperstimulation in cancer patients: the state of the art

Quality of life of young cancer survivors has become a major issue. However, anticancer therapies can have a detrimental impact on fertility. It is now well-established that all patients should receive information about the fertility risks associated with their cancer treatment and the fertility preservation options available. Currently, oocyte or embryo banking after controlled ovarian hyperstimulation represents the most effective method for preserving female fertility. Over the past years innovative protocols of ovarian stimulation have been developed to enable cancer patients to undergo oocyte or embryo cryopreservation irrespective of the phase of the cycle or without exogenous follicle-stimulating hormone-related increase in serum estradiol levels. The present article reviews the different protocols of ovarian hyperstimulation for cancer patients, candidates for fertility preservation.

Pregnancy-related venous thrombosis: comparison between spontaneous and ART conception in an Italian cohort

OBJECTIVE

To evaluate in an Italian cohort the incidence of venous thromboembolic events (VTE) in pregnancies after assisted reproductive technologies (ART).

SETTING

Thrombosis and Haemostasis Unit at I.R.C.C.S. 'Casa Sollievo della Sofferenza', S. Giovanni Rotondo.

PARTICIPANTS

A prospective cohort of 998 women advised to undergo ART was referred by local fertility clinics from April 2002 to July 2011. Follow-up information was obtained during the check-up and/or by phone interviews. In a cohort of women who consecutively gave birth (n=3339) after spontaneous conception in our Institution, information on the diagnoses of pregnancy-related venous thromboses was obtained by linkage to a patient administrative register.

PRIMARY AND SECONDARY OUTCOME MEASURES

We calculated the incidence of VTE and superficial venous thrombosis in successful ART cycles and compared it with that of the general population conceiving spontaneously.

RESULTS

Overall, 684 ART cycles were carried out by 234 women, who achieved a clinical pregnancy; in case of more than one successful cycle, only the first pregnancy was considered. Three vein thromboses (two VTE and one superficial vein thrombosis) were recorded. An antithrombotic prophylaxis with LMWH alone or combined with low-dose aspirin was prescribed in 23/234 (9.8%) women. In the reference cohort of 3339 women, a total of 11 vein thromboses were observed: six VTE and five SVT. The two-tailed Fisher exact test showed a trend towards statistical significance (p: 0.06, OR: 3.9, 95% CI 0.87 to 15.3). After the exclusion of superficial thromboses in both the groups, we found that the incidence of VTE in our population of women who had undergone ART was 2/234 pregnancies (8.5 ‰), whereas that in our reference population was 6/3339 (1.8 ‰) (p: 0.09).

CONCLUSIONS

Our data show a slightly higher incidence of vein thromboses in pregnancies after ART than in those after natural conception.

Thromboembolism incidence and prophylaxis during vaginal delivery hospitalizations

OBJECTIVE

Although major international guidelines recommend venous thromboembolism (VTE) prophylaxis during vaginal delivery hospitalization for women with additional risk factors, US guidelines recommend prophylaxis for a very small number of women who are at particularly high risk for an event. The purpose of this study was to characterize practice patterns of VTE prophylaxis in the United States during vaginal delivery hospitalizations and to determine VTE incidence in this population.

STUDY DESIGN

A population-level database was used to analyze VTE incidence and use of VTE prophylaxis during vaginal delivery hospitalizations in the United States between 2006 and 2012 (n = 2,673,986). We evaluated whether patients received either pharmacologic or mechanical prophylaxis. Hospital-level factors and patient characteristics were included in multivariable regression analysis that evaluated prophylaxis administration.

RESULTS

We identified 2,673,986 women who underwent vaginal delivery. Incidence of VTE increased during the study period from 15.6-29.8 events per 100,000 delivery hospitalizations. Within the cohort, 2.6% of patients (n = 68,835) received VTE prophylaxis. Pharmacologic prophylaxis was rare; <1% of women received unfractionated or low-molecular-weight heparin. Although patients with thrombophilia or a previous VTE event were likely to receive prophylaxis (60.8% and 72.8%, respectively), patients with risk factors for VTE such as obesity, smoking, and heart disease were unlikely to receive prophylaxis (rates of 5.9%, 3.3%, and 6.2%, respectively).

CONCLUSION

Our findings demonstrate that the administration of VTE prophylaxis outside a small group of women at extremely high risk for VTE is rare during vaginal delivery hospitalization. Given that VTE incidence is rising in this population, further research to determine whether broadening prophylaxis for VTE may reduce severe maternal morbidity and death is indicated.

Anticoagulation and in vitro fertilization and ovarian stimulation

Assisted reproductive technology is widely used to treat couples affected by infertility. Complications associated with assisted reproduction include venous thromboembolism, ovarian hyperstimulation syndrome, and recurrent implantation failure. It has also been proposed that thrombophilia may be associated with an increased likelihood of these events. Although data are limited, antithrombotic therapy is frequently used to enhance the likelihood of successful assisted reproduction. This chapter reviews the risks of venous and arterial thromboembolism associated with assisted reproduction, as well as available data regarding the impact of thrombophilia on the risks of thromboembolism and failure of implantation. The role of antithrombotic therapy in reducing the likelihood of these events, along with recommendations from various guidelines, are also discussed.

Thrombosis following ovarian hyperstimulation syndrome

The aim of this review is to analyse the pathophysiology and complications of thrombosis in conjuction with ovarian hyperstimulation syndrome (OHSS) following ovulation induction and to suggest practical guidelines usefull for the prevention and treatment. Although the incidence of thrombosis varies from 0.2% among in vitro fertilization (IVF) cycles and up to 10% for severe cases of the syndrome, it represents the most dangerous complication of OHSS. Different changes in haemostatic markers have been found to create a state of hypercoagulability, but no single standard test is available to estimate the state of thrombosis. The role of markers for thrombophilia is controversial. Thromboses are mostly venous (67-75%) involving upper limbs and neck, then arterial (25-33%) which are mainly intracerebral. The predominant sites of venous thromboembolism in the upper part of the body may be explained by higher concentrations of estrogens drained through lymphatic ducts from ascites and by compression of rudimentary branchyal cysts. Once early diagnosis is established, it is crucial to use an anticoagulant treatment with heparin proceeded with thromboprophylaxis. However, identification of patients at risk and preventive measures of OHSS are the best means in reducing the risk of thrombosis after ovarian stimulation.

[Pharmacological thromboprophylaxis in gynecology and obstetrics]

Venous thromboembolism (VTE) is associated with high morbidity and mortality. Therefore, effective methods for safe thromboprophylaxis remain an ongoing challenge in daily clinical practice. This is especially true for pregnant women and patients with gynaecological malignancies. Low-molecular weight heparins continue to be agents of choice for pharmacological thromboprophylaxis postoperatively, in pregnant patients at risk, and during the puerperium. However, these drugs can cause bleeds or heparin-induced thrombocytopenia (type II). Based on recent revisions of corresponding guidelines, this article provides an overview of the current state of pharmacological thromboprophylaxis and discusses prevailing problems and unresolved issues.

Risk of thrombosis in women with malignancies undergoing ovarian stimulation for fertility preservation

BACKGROUND

Compared with the general population, cancer patients have a higher risk of venous thromboembolism as well as arterial thrombotic events such as stroke, myocardial infarction and peripheral arterial embolism. Therefore a possible concern for women with malignancies undergoing ovarian stimulation for fertility preservation is the increased risk of venous or arterial thrombosis.

METHODS

In this article, we revised current available literature on the risk of thrombosis in patients with cancer and in women undergoing ovarian stimulation, with the ultimate aim of drawing some indications for preventive measures.

RESULTS

Unfortunately, there are no specific data on the risk of thrombosis in women with cancer undergoing ovarian stimulation for fertility preservation. However, the literature suggests that the cancer type and stage, surgery, and chemotherapy all influence the risk of venous and, possibly, arterial thrombosis. Reports of cases of ovarian stimulation in women without malignancies have shown that venous thrombosis rarely occurs unless a pregnancy is achieved, while arterial thrombosis can occur in the absence of pregnancy but is usually only associated with ovarian hyperstimulation syndrome (OHSS). OHSS increases the risk of thrombotic events, but only the early form of the syndrome is relevant for women undergoing fertility preservation.

CONCLUSIONS

The available evidence on the risks of thrombosis for women undergoing ovarian stimulation for fertility preservation due to a malignancy is reassuring. However the avoidance of the early form of OHSS in women preserving oocytes/embryos due to malignancy is crucial. For these cycles, we advocate the use of a regimen of ovarian stimulation with gonadotrophin releasing hormone (GnRH) antagonists using GnRH agonists to trigger ovulation, an approach that has been shown to markedly reduce the risk of OHSS. Antithrombotic prophylaxis should be administered only to selected subgroups of women such as those with other risk factors or those who do develop early OHSS.

Pregnancy-Related Venous Thromboembolism

Pregnancy is associated with an increased risk of venous thromboembolism (VTE), with a reported incidence ranging from 0.49 to 2 events per 1000 deliveries. Risk factors include advanced maternal age, obesity, smoking, and cesarian section. Women with a history of previous VTE are at a 4-fold higher risk of recurrent thromboembolic events during subsequent pregnancies. Additionally, the presence of concomitant thrombophilia, particularly factor V Leiden (homozygosity), prothrombin gene mutation (homozygosity), or antiphospholipid syndrome (APS), increases the risk of pregnancy-related VTE. Low-molecular-weight heparin (LMWH) and unfractionated heparin (UFH) are the drugs of choice for anticoagulation during pregnancy. LMWH is preferred due to ease of use and lower rates of adverse events. Women with high thromboembolic risk particularly those with a family history of VTE should receive antepartum thromboprophylaxis. Women with low thromboembolic risk or previous VTE caused by a transient risk factor (ie, provoked), who have no family history of VTE, may undergo antepartum surveillance. Postpartum anticoagulation can be considered in women with both high and low thromboembolic risk.

Clinical syndromes associated with acquired antithrombin deficiency via microvascular leakage and the related risk of thrombosis

Antithrombin (AT) is a 65kDa glycoprotein belonging to a group of inhibitory factors known as serpins (serine protease inhibitors). It plays a critical role in the inhibition of coagulation and inflammation processes within the environment of the vascular endothelium. Inadequate levels of functional AT in plasma results in an increased risk of thrombotic events, both venous and arterial. AT deficiency can be inherited or acquired. Congenital AT deficiency is the most severe inherited thrombophilic condition with an odds ratio of 20 for the increased risk of venous thrombosis. Acquired AT deficiency occurs in a variety of physiologic and pathologic medical conditions with similar risks of increased thrombosis. In this article, we review clinical settings characterized by an acquired AT deficiency largely or partly subsequent to protein microvascular leakage. Other different mechanisms of AT depletion are implied in some clinical conditions together with endothelial loss, and, therefore, outlined. In addition, we provide a description of the current knowledge on the specific mechanisms underlying endothelial AT leakage and on the consequences of this protein decrease, specifically looking at thrombosis. We identify potential directions of research that might prove useful in patients with acquired AT deficiency.