Low-dose aspirin for in vitro fertilization or intracytoplasmic sperm injection: a systematic review and a meta-analysis of the literature

Body mass index modified the effectiveness of low dose aspirin treatment on frozen-thawed embryo transfer outcome: a propensity score-matched study

Background

Low-dose aspirin is one of the widely used adjuvants in assisted reproductive technologies with the hope of improving the live birth rate. However, the studies regarding its effects are conflicting. The study aimed to investigate the association between aspirin administration and live birth following frozen-thawed embryo transfer (FET) in patients with different body mass index (BMI).

Methods

A retrospective cohort study was performed on 11,993 patients receiving FET treatments. 644 of which received a low-dose aspirin (100 mg/day) during endometrial preparation until 10 weeks after transfer. Propensity score matching was performed to avoid selection biases and potential confounders.

Results

The clinical pregnancy rate and live birth rate were similar before matching (54.4% versus 55.4%, RR: 1.02, 95%CI: 0.95-1.09, and 46.3 versus 47.8, RR: 1.03, 95%CI: 0.95-1.12 respectively). A weak association in favor of aspirin administration was found in the matched cohort (49.5% versus 55.4%, RR: 1.12, 95%CI: 1.01-1.24, and 41.9% versus 47.8%, RR: 1.14, 95%CI: 1.01-1.29 respectively). However, when stratified the patients with WHO BMI criteria, a significant increase in live birth rate associated with aspirin treatment was found only in patients with low BMI (<18.5 kg/m2) in either unmatched (46.4% versus 59.8%, RR:1.29, 95%CI:1.07-1.55) or matched cohort (44% versus 59.8%, RR: 1.36, 95%CI: 1.01-1.83) but not in patients with higher BMI categories. With the interaction analysis, less association between aspirin and live birth appeared in patients with normal BMI (Ratio of OR:0.49, 95%CI: 0.29-0.81) and high BMI (Ratio of OR:0.57, 95%CI: 0.27-1.2) compared with patients with low BMI.

Conclusion

BMI may be considered when evaluating aspirin's effect in FET cycles.

Immunomodulation for unexplained recurrent implantation failure: where are we now?

In brief

Immune dysfunction may contribute to or cause recurrent implantation failure. This article summarizes normal and pathologic immune responses at implantation and critically appraises currently used immunomodulatory therapies.

Abstract

Recurrent implantation failure (RIF) may be defined as the absence of pregnancy despite the transfer of ≥3 good-quality blastocysts and is unexplained in up to 50% of cases. There are currently no effective treatments for patients with unexplained RIF. Since the maternal immune system is intricately involved in mediating endometrial receptivity and embryo implantation, both insufficient and excessive endometrial inflammatory responses during the window of implantation are proposed to lead to implantation failure. Recent strategies to improve conception rates in RIF patients have focused on modulating maternal immune responses at implantation, through either promoting or suppressing inflammation. Unfortunately, there are no validated, readily available diagnostic tests to confirm immune-mediated RIF. As such, immune therapies are often started empirically without robust evidence as to their efficacy. Like other chronic diseases, patient selection for immunomodulatory therapy is crucial, and personalized medicine for RIF patients is emerging. As the literature on the subject is heterogenous and rapidly evolving, we aim to summarize the potential efficacy, mechanisms of actions and side effects of select therapies for the practicing clinician.

Prophylaxis and management of venous thromboembolism during pregnancy and postpartum period

Introduction. Venous thromboembolism (VTE) is one of the lead causes for maternal mortality and morbidity during pregnancy in the majority of developed countries. The incidence rate of VTE per pregnancy-year increases during pregnancy and postpartum period about by 4-fold and at least 14-fold, respectively.

Aim: to analyze and summarize current view on risk factors of thrombotic events during gestation and to discuss recent guidelines for the management of venous thromboembolic complications during pregnancy and postpartum, by taking into account a balance between risks and benefits of using anticoagulants.

Materials and Methods. The literature search covering the last 10 years was carried out in the electronic scientific databases RSCI, PubMed/MEDLINE, and Embase. While formulating a search strategy for evidence-based information, the PICO method (P = Patient; I = Intervention; C = Comparison; O = Outcome) and the key terms “venous thromboembolism” and “pregnancy” were used.

Results. Risk factors were found to include a personal history of VTE, verified inherited or acquired thrombophilia, a family history of VTE and general medical conditions, such as immobilization, overweight, varicose veins, some hematological diseases and autoimmune disorders. VTE is considered being potentially preventable upon prophylactic administration of anticoagulants, but no high confidence randomized clinical trials comparing diverse strategies of thromboprophylaxis in pregnant women have been proposed so far. Because heparins do not cross the placenta, weight-adjusted therapeutic-dose low molecular weight heparins (LMWH) represent the anticoagulant treatment of choice for VTE during pregnancy. Once- and twice-daily dosing regimens are acceptable. However, no evidence suggesting benefits for measurement of factor Xa activities and consecutive LMWH dose adjustments to improve clinical outcomes are available. In case of uncomplicated pregnancy-related VTE, no routine administration of vitamin K antagonists, direct thrombin or factor Xa inhibitors, fondaparinux, or danaparoid is recommended. Lactating women may switch from applying LMWH to warfarin. Anticoagulation therapy should be continued for 6 weeks postpartum with total duration lasting at least for 3 months.

Conclusion. VTE is a challenging task in pregnant women expecting to apply a multi-faceted approach for its efficient solution by taking into account updated recommendations and personalized patient-oriented features.

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.

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.

In vitro Fertilization Procedures with Embryo Transfer and Their Association with Thrombophilia, Thrombosis and Early Antithrombotic Treatments

In vitro fertilization (IVF) procedures have been frequently associated with antithrombotic treatments, in particular, to aspirin or low-molecular-weight heparin (LMWH). The rationale of this treatment is based on the increase of thrombotic risk occurring in this clinical context. Indeed, both prothrombotic changes of coagulation parameters specifically related to IVF procedures as well as the presence of potential thrombophilic alterations may concur to increase the risk in these women. Furthermore, the presence of thrombophilia has been suggested as a potential cause of recurrent IVF failures. Therefore, antithrombotic treatments have been historically planned to prevent thrombotic disorders during pharmacological ovarian stimulation and/or to increase a successful rate of pregnancy and live births after IVF with embryo transfer. However, up to date, the role of inherited and\or acquired thrombophilia is still debated as well as a univocal therapeutic approach is lacking in women with infertility. The administration of antithrombotic drugs differs in several studies and even the dosages of aspirin and\or low-molecular-weight heparin are different. This review focuses on underlining current evidence on the role of thrombophilia and thromboprophylaxis in women selected for IVF with embryo transfer.

Analgesic use at ovulation and implantation and human fertility

BACKGROUND

Studies investigating the effects of pain-relieving medication use on conceiving a pregnancy have shown conflicting results. Furthermore, no previous study has examined medication use around ovulation or implantation and the associations with the probability of conception, fecundability.

OBJECTIVE

The objective of the study was to explore the association between fecundability and analgesic use in 3 different menstrual cycle windows (preovulation, periovulation, and implantation) as well as across the entire menstrual cycle.

STUDY DESIGN

We analyzed data from a prospective cohort study of women between 30 and 44 years of age who were trying to conceive naturally from 2008 through 2015. Using daily diaries, medication usage was classified as acetaminophen, aspirin, or nonaspirin nonsteroidal antiinflammatory drug during 4 time periods of interest (preovulatory, periovulatory, and implantation) as well as the overall nonmenstrual bleeding days of the cycle. Menstrual cycles during the prospective attempt to become pregnant were enumerated using daily diary menstrual bleeding information. Conception was defined as a positive home pregnancy test. Discrete time fecundability models were used to estimate the fecundability ratio and 95% confidence interval in each of the 4 time windows of interest and for each pain reliever (aspirin use, nonaspirin nonsteroidal antiinflammatory drug use, acetaminophen) compared with no medication use after adjustment for several covariates including age, race, education, body mass index, alcohol and caffeine use, frequency of intercourse, and a history of migraines or uterine fibroids.

RESULTS

Medication use was infrequent in the 858 women and 2366 cycles in this analysis. Use of nonaspirin nonsteroidal antiinflammatory drugs or acetaminophen was not associated with fecundability in any of the time windows of interest. Although the sample size was small, aspirin use during the implantation window was associated with increased fecundability (adjusted fecundability ratio [confidence interval]: 2.05 [1.23-3.41]). This association remained when limiting the analysis to cycles with minimal missing data or when adjusting for gravidity. None of the other medications were associated with fecundability.

CONCLUSION

Aspirin use around implantation was associated with increased fecundability. These results expand previous literature to suggest the following: (1) implantation may be an important target for the effects of aspirin on conception and (2) aspirin may be beneficial, regardless of pregnancy loss history. These observations should be tested with a clinical trial.

Does low-dose aspirin initiated before 11 weeks' gestation reduce the rate of preeclampsia?

OBJECTIVE DATA

Preconception or early administration of low-dose aspirin might improve endometrial growth, placental vascularization, and organogenesis. Most studies have evaluated the potential benefit of preconception or early administration of low-dose aspirin in women with a history of recurrent pregnancy loss, women who have undergone in vitro fertilization, or women with thrombophilia or antiphospholipid syndrome. These women are at an increased risk of placenta-associated complications of pregnancy, including preeclampsia, preterm delivery, and fetal growth restriction.

STUDY OUTCOMES

We performed a systematic review and meta-analysis to evaluate the effect of low-dose aspirin initiated at <11 weeks' gestation on the risk of preeclampsia, gestational hypertension, or any hypertensive disorder of pregnancy. Secondary outcomes included preterm delivery at <37 weeks' gestation and fetal growth restriction.

STUDY APPRAISAL AND SYNTHESIS METHODS

We searched in MEDLINE via PubMed, EMBASE, Cochrane Central Register of Controlled Trials (CENTRAL), ClinicalTrials.gov, and the World Health Organization International Clinical Trials Registry Platform from 1985 to November 2018. Entry criteria were randomized controlled trials evaluating the effect of aspirin administered at <11 weeks' gestation in preventing preeclampsia and/or hypertensive disorders in pregnancy or improving pregnancy outcomes in women with recurrent miscarriage as compared with placebo or no treatment and outcome data available or provided by authors for >85% of the study population. Relative risks with 95% confidence intervals were calculated for each study and pooled for global analysis as the effect measure. We assessed statistical heterogeneity in each meta-analysis using the χ² statistics, I², and Tau². Heterogeneity was considered substantial if an I² was greater than 50% and either the Tau² was greater than zero or there was a low P value (<0.10) in the χ² test for heterogeneity. Random-effects meta-analysis, weighted by the size of the studies, was performed to produce an overall summary on aspirin effect for each outcome. Sensitivity analysis by sequential omission of each individual study and by fixed-effects model was performed. Publication bias was not assessed because of the small number of included studies. Statistical analysis was performed using Stata release 14.0 (StataCorp).

RESULTS

The entry criteria were fulfilled by 8 randomized controlled trials on a combined total of 1426 participants. Low-dose aspirin initiated at <11 weeks' gestation was associated with a nonsignificant reduction in the risk of preeclampsia (relative risk, 0.52; 95% confidence interval, 0.23-1.17, P = .115), gestational hypertension (relative risk, 0.49; 95% confidence interval, 0.20-1.21; P = .121), and any hypertensive disorder of pregnancy (relative risk, 0.59; 95% confidence interval, 0.33-1.04, P = .067). Early administration of low-dose aspirin reduced the risk of preterm delivery (relative risk, 0.52; 95% confidence interval, 0.27-0.97, P = .040) but had no impact on the risk of fetal growth restriction (relative risk, 1.10; 95% confidence interval, 0.58-2.07, P = .775). Except for preterm delivery and any hypertensive disorder of pregnancy, sensitivity analysis demonstrated similar observations, therefore confirming the robustness of the analysis.

CONCLUSION

The administration of low-dose aspirin at <11 weeks' gestation in women at high risk does not decrease the risk of preeclampsia, gestational hypertension, any hypertensive disorder of pregnancy, and fetal growth restriction. However, it might reduce the risk of preterm delivery. Larger randomized controlled trials will be required to substantiate the findings.

American Society of Hematology 2018 guidelines for management of venous thromboembolism: venous thromboembolism in the context of pregnancy

BACKGROUND

Venous thromboembolism (VTE) complicates ∼1.2 of every 1000 deliveries. Despite these low absolute risks, pregnancy-associated VTE is a leading cause of maternal morbidity and mortality.

OBJECTIVE

These evidence-based guidelines of the American Society of Hematology (ASH) are intended to support patients, clinicians and others in decisions about the prevention and management of pregnancy-associated VTE.

METHODS

ASH formed a multidisciplinary guideline panel balanced to minimize potential bias from conflicts of interest. The McMaster University GRADE Centre supported the guideline development process, including updating or performing systematic evidence reviews. The panel prioritized clinical questions and outcomes according to their importance for clinicians and patients. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach was used to assess evidence and make recommendations.

RESULTS

The panel agreed on 31 recommendations related to the treatment of VTE and superficial vein thrombosis, diagnosis of VTE, and thrombosis prophylaxis.

CONCLUSIONS

There was a strong recommendation for low-molecular-weight heparin (LWMH) over unfractionated heparin for acute VTE. Most recommendations were conditional, including those for either twice-per-day or once-per-day LMWH dosing for the treatment of acute VTE and initial outpatient therapy over hospital admission with low-risk acute VTE, as well as against routine anti-factor Xa (FXa) monitoring to guide dosing with LMWH for VTE treatment. There was a strong recommendation (low certainty in evidence) for antepartum anticoagulant prophylaxis with a history of unprovoked or hormonally associated VTE and a conditional recommendation against antepartum anticoagulant prophylaxis with prior VTE associated with a resolved nonhormonal provoking risk factor.

Embryo transfer strategy and therapeutic options in infertile patients with thin endometrium: a systematic review

Human endometrium has a key role in implantation process. The measurement of endometrial thickness is the most commonly used in clinical practice. Managing patients with thin endometrium still represents a major challenge for clinicians. The objective of this systematic review was to investigate all available interventions to improve endometrial thickness (EMT) in women with history of thin endometrium undergoing fresh or frozen-thawed embryo transfers (ET). We performed a comprehensive search of relevant studies from January 1978 to February 2018. The different strategies were categorized as hormonal, vascular, and growth factor approaches and specifically analyzed according to the type of ET. Thirty-one studies were included. Overall, quality of the evidence ranged from very low to moderate, with only few randomized controlled trials that support the use of either GnRH analogues in fresh ET or sildenafil in frozen ET for enhancing endometrial growth. Besides, intensified estradiol administration is a common approach that might improve EMT in frozen ET. The present review evidences the paucity of reliable data regarding the efficiency of different interventions aiming at increasing EMT before fresh or frozen-thawed ET. Robust and high-quality randomized controlled trials are still needed before guidelines can be established.

Effect of low-dose aspirin on the development of ovarian hyperstimulation syndrome and outcomes of assisted reproductive techniques in the women with PCOS, a randomized double-blinded clinical trial

OBJECTIVE

Ovarian hyperstimulation syndrome (OHSS) is a major complication of assisted reproductive technologies (ART). Polycystic ovary syndrome (PCOS) is a risk factor for OHSS. The aim of this randomized clinical trial (RCT) was to study the effect of low-dose aspirin (LDA) on the development of OHSS and ART outcomes in PCOS during ART.

MATERIALS AND METHODS

This double-blinded placebo controlled RCT was performed on 232 PCOS infertile women in their first ART cycles during 2010-2016. LDA and placebo capsules were prepared, packed and specified by code numbers in similar shapes. One package was given to every woman and asked to take one capsule/day since the 21st day of her cycle prior to the gonadotropin stimulation. Gonadotropin releasing hormone agonist long protocol and triggering by human chorionic gonadotropin were used. Development of moderate to severe OHSS and their ART outcomes were documented then the codes were broken and data analyzed. Chi-square and Mann-Whitney U tests were used for the statistical analyses.

RESULTS

Eighteen cases that did not follow the study design were excluded. 214 cycles remained for the final analyses with 109 cases in LDA and 105 in the placebo group. Rate of the moderate to severe OHSS in LDA group was 34.9% compared to 30.5% in placebo group (P = 0.494). Fertilization rate was 71.8% vs 65.1% (P = <0.001) and the mean number of grade III embryos were 3.28 ± 3.53 vs 1.46 ± 1.42 (P = 0.014) in LDA and placebo groups, respectively. The mean number of the oocytes in different grades, total and frozen embryos also implantation and clinical pregnancy rates were not different between the groups.

CONCLUSION

Moderate to Severe OHSS was not decreased but fertilization rate and the mean number of poor quality embryos were increased in LDA arm.

REGISTRATION NUMBER

IRCT 201105216541N1.

Effect of preconception low dose aspirin on pregnancy and live birth according to socioeconomic status: A secondary analysis of a randomized clinical trial

Low socioeconomic status (SES) is associated with adverse pregnancy outcomes and infertility. Low-dose aspirin (LDA) was shown to improve livebirth rates in certain subsets of women, and therefore, may impact pregnancy rates differentially by SES status. Therefore, the aim of the current study was to examine whether daily preconception-initiated LDA affects rates of pregnancy, livebirth, and pregnancy loss differently across strata of socioeconomic status (SES). This is a secondary analysis of The Effects of Aspirin in Gestation and Reproduction (EAGeR) Trial, a multisite, block- randomized, placebo-controlled trial conducted at four U.S. medical centers (n = 1,228, 2007–2012). Women attempting spontaneous conception with a history of pregnancy loss were randomly allocated preconception to 81mg of aspirin + 400mcg of folic acid (n = 615) or placebo + 400mcg of folic acid (n = 613). Study medication was administered for six menstrual cycles or until 36 weeks’ gestation if pregnancy was achieved. For this analysis, women were stratified by SES, which included income (low, mid, high) and a combined grouping of education and income (low-low, low-high, high-low, high-high). Log binomial models with robust variance estimated risks of pregnancy, livebirth, and pregnancy loss for LDA versus placebo. LDA increased pregnancy and livebirth rates (RR 1.23, 95% CI: 1.03, 1.45) in the high-income, but not mid- or low-income groups. LDA increased pregnancy rates in both the low education-low income group (RR 1.22, 95% CI: 1.02, 1.46) and the high education-high income group (RR 1.23, 95%CI: 1.06, 1.42), with no effect observed in mid-SES groupings. LDA, a low-cost and widely available treatment, may be particularly beneficial to women at the highest and lowest ends of the socioeconomic spectrum, though underlying mechanisms of this disparity are unclear. Confirming these findings and identifying factors which may modulate the effectiveness of LDA will ultimately facilitate personalized clinical care and improvements in population-level reproductive health.

Trial registration number: ClinicalTrials.gov, NCT00467363.

The role of immunotherapy in in vitro fertilization: a guideline

Adjuvant immunotherapy treatments in in vitro fertilization (IVF) aim to improve the outcome of assisted reproductive technology (ART) in both the general ART population as well as subgroups such as patients with recurrent miscarriage or implantation failure. The purpose of this guideline is to evaluate the role of immunomodulating therapy in ART. Unfortunately, many of the evaluated therapies lack robust evidence from well-designed adequately powered randomized controlled trials to support their use. Immunotherapies reviewed in the present document are either not associated with improved live-birth outcome in IVF or have been insufficiently studied to make definitive recommendations.

In vitro fertilization outcomes in women with antiphospholipid antibodies circulation

Background: Antiphospholipid antibodies (aPL) have a multifaceted effect on the hemostatic system, damaging all its protective links.Aim: To study the effect of APA on outcomes of assisted reproductive technologies (ART).Study design: We examined 267 women with infertility, who planned pregnancy using ART. They included 178 women with IVF failure (I group) and 89 women with pregnancy after the IVF program (II group). The comparison group consisted of 80 pregnant women after IVF (male factor); a control group included 80 pregnant women with physiological pregnancy. Results of study demonstrated a high frequency of aPL circulation in a group of women with IVF failures. Overall, the proportion of aPL among all 267 women who planned pregnancy with ART was 32.6%. Elevated levels of aPL in the structure of causes of IVF failures (group I) were observed in 42.1% of them. Among women whose pregnancy occurred with ART (II group) the rate of APA was 19.1%. In the comparison group, in 6.3% of cases, aPL circulation was observed. In the control group, the rate was 3.4%.Conclusion: Considering the high percentage of aPL circulation in the case of IVF failures, authors think that high titers of aPL are a temporary contraindication for IVF. Patients with a history of aPL circulation are required to receive anticoagulant therapy from the first days of the hormonal protocol. The drug of choice is a group of low molecular weight heparins (LMWH). An individual approach is extremely important with the possible identification of causes of IVF failures and selective therapy, which leads to a significant improvement in the outcomes of the IVF program.

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.

Efficacy of low-molecular-weight heparin on the outcomes of in vitro fertilization/intracytoplasmic sperm injection pregnancy in non-thrombophilic women: a meta-analysis

Introduction

The aim of our study was to evaluate the effect of low‐molecular‐weight heparin on pregnancy outcomes in women without thrombophilia during in vitro fertilization/intracytoplasmic sperm injection treatment.

Material and methods

We searched Pubmed, Web of Science, Embase, Cochrane and CNKI (from inception to 2 February 2018). Our study identified randomized controlled trials or quasi‐randomized controlled trials comparing low‐molecular‐weight heparin subcutaneous treatment with no treatment or only luteal support control. The outcomes included live birth rate, clinical pregnancy rate and miscarriage rate.

Results

Five trials, including 935 women receiving in vitro fertilization/intracytoplasmic sperm injection treatment, were included in meta‐analyses. There were 458 women receiving low‐molecular‐weight heparin and 477 in the control group. No significant differences for live birth rate, clinical pregnancy rate and miscarriage rate were found between the low‐molecular‐weight heparin and control groups. Of them, four trials reported live birth rate as an outcome and the risk ratio was 1.13 (95% confidence interval 0.88–1.43, p = 0.34). All five trials reported clinical pregnancy rate as an outcome, the risk ratio was 1.08 (95% confidence interval 0.87–1.32, p = 0.47). Three trials reported miscarriage rate and the risk ratio was 0.58 (95% confidence interval 0.30–1.10, p = 0.09). In women with two or more failed in vitro fertilization/intracytoplasmic sperm injection cycles, the risk ratio of live birth rate was 1.15 and the risk ratio of clinical pregnancy rate was 1.17. In women with three or more failed in vitro fertilization/intracytoplasmic sperm injection cycles, the risk ratios of live birth rate and clinical pregnancy rate were 1.36 and 1.35, respectively.

Conclusions

Our results suggested that low‐molecular‐weight heparin had no effect on pregnancy success rate in non‐thrombophilic women undergoing in vitro fertilization/intracytoplasmic sperm injection treatment. However, to justify the use of low‐molecular‐weight heparin in clinical practice, multicenter trials are still necessary.

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

INTRODUCTION

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSIONS

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

The Effects of Aspirin in Gestation and Reproduction (EAGeR) Trial: A Story of Discovery

Human reproduction is an inefficient process. There are several drivers of complications along the path to and during pregnancy, one of which is inflammation. Treatments to mitigate the deleterious effects of aberrant inflammation with something inexpensive and widely available like aspirin could have dramatic global impact. The Effects of Aspirin in Gestation and Reproduction (EAGeR) trial enrolled women aged 18 to 40 years with one to two prior pregnancy losses and no diagnosis of infertility. Patients were randomized to either low-dose aspirin or placebo. Here, we review the collective findings of the EAGeR trial to date and discuss several important lessons learned from the unique data resulting from this groundbreaking trial. Findings reported from this trial provide significant advances in the understanding of aspirin’s potential mechanisms in modulating reproductive processes and the role of inflammation in these processes. This review describes the collective findings of the EAGeR trial in the context of the existing literature regarding aspirin and inflammation in reproduction to inform relevant next steps in fertility and obstetric research, as well as potential implications for clinical care.

Aspirin for in vitro fertilisation

BACKGROUND

Aspirin is used with the aim of optimising the chance of live birth in women undergoing assisted reproductive technology (ART), despite inconsistent evidence of its efficacy and safety (in terms of intraoperative bleeding during oocyte retrieval and risk of miscarriage). The most appropriate time to commence aspirin therapy and the length of treatment required are also still to be determined. This is the second update of the review first published in 2007.

OBJECTIVES

To evaluate the effectiveness and safety of aspirin in women undergoing ART.

SEARCH METHODS

We searched the Cochrane Gynaecology and Fertility Group Trials Register, Cochrane Central Register of Controlled Trials (CENTRAL; 2016, Issue 4) in the Cochrane Library (searched 9 May 2016); the databases MEDLINE (1946 to 9 May 2016) and Embase (1974 to 9 May 2016); and trial registers (ClinicalTrials.gov and the World Health Organization International Clinical Trials Registry Platform search portal). We also examined the reference lists of all known primary studies and review articles, citation lists of relevant publications and abstracts of major scientific meetings, combined with the Cochrane Gynaecology and Fertility Group's search strategy.

SELECTION CRITERIA

Randomised controlled trials on aspirin for women undergoing ART.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trial eligibility and risk of bias and extracted the data. The primary review outcome was live birth. Secondary outcomes included clinical pregnancy, ongoing pregnancy, multiple pregnancy, miscarriage, and other complications associated with IVF/ICSI or with pregnancy and birth. We combined data to calculate risk ratios (RRs) (for dichotomous data) and mean differences (MDs) (for continuous data) and 95% confidence intervals (CIs). Statistical heterogeneity was assessed using the I² statistic. We assessed the overall quality of the evidence for the main comparisons using GRADE methods.

MAIN RESULTS

The search identified 13 trials as eligible for inclusion in the review, including a total of 2653 participants with a mean age of 35 years. Ten studies used a dose of 100 mg and three used 80 mg of aspirin per day. In most of them, aspirin was commenced immediately at the start of down-regulation, while the duration of treatment varied widely. Eight studies provided a placebo for the control group.There was no evidence of a difference between the aspirin group and the group receiving no treatment or placebo in rates of live birth (RR 0.91, 95% CI 0.72 to 1.15, 3 RCTs, n = 1053, I² = 15%, moderate-quality evidence). In addition, clinical pregnancy rates were also similar for the two groups (RR 1.03, 95% CI 0.91 to 1.17, 10 RCTs, n = 2142, I² = 27%, moderate-quality evidence); sensitivity analysis, excluding studies at high risk of bias, did not change the effect estimate. There was no evidence of a difference between groups in terms of multiple pregnancy as confirmed by ultrasound (RR 0.67, 95% CI 0.37 to 1.25, 2 RCTs, n = 656, I² = 0%, low-quality evidence), miscarriage (RR 1.10, 95% CI 0.68 to 1.77, 5 RCTs, n = 1497, I² = 0%, low-quality evidence), ectopic pregnancy (RR 1.86, 95% CI 0.75 to 4.63, 3 RCTs, n = 1135, I² = 0%, very low quality evidence) or vaginal bleeding (RR 1.01, 95% CI 0.14 to 7.13, 1 RCT, n = 487, very low quality evidence). Data were lacking on other adverse effects.The overall quality of the evidence ranged from very low to moderate; limitations were poor reporting of study methods and suspected publication bias.

AUTHORS' CONCLUSIONS

Currently there is no evidence in favour of routine use of aspirin in order to improve pregnancy rates for a general IVF population. This is based on available data from randomised controlled trials, where there is currently no evidence of an effect of aspirin on women undergoing ART, as there is no single outcome measure demonstrating a benefit with its use. Furthermore, current evidence does not exclude the possibility of adverse effects.

Expanded findings from a randomized controlled trial of preconception low-dose aspirin and pregnancy loss

STUDY QUESTION

What is the association between daily preconception-initiated low-dose aspirin (LDA) treatment and very early pregnancy losses or euploid (chromosomally normal) losses among women with one to two prior losses?

SUMMARY ANSWER

Daily LDA initiated preconception was not associated with the rate or type of pregnancy loss among women with a history of one to two prior pregnancy losses.

WHAT IS KNOWN ALREADY

LDA is often used to treat recurrent pregnancy loss with reductions in pregnancy loss generally only observed among women with antiphospholipid antibodies, and null associations observed among women without antiphospholipid antibodies. We previously evaluated the association between LDA and pregnancy loss overall among women with one to two prior losses in the Effects of Aspirin in Gestation and Reproduction (EAGeR) trial and found no association, though did not distinguish between potential effects at different stages of pregnancy loss, including implantation failure, or between euploid and aneuploid losses.

STUDY DESIGN, SIZE, DURATION

The EAGeR trial was a multi-site prospective block-randomized double-blind placebo-controlled trial. In total, 1228 women were randomized to daily LDA (81 mg/day) plus folic acid (400 mcg/day), or placebo plus folic acid. Participants were assigned study drug for less than or equal to six menstrual cycles or if they conceived, throughout pregnancy with study drug discontinued at 36 weeks gestation. This analysis includes additional outcome information obtained from chart abstractions after the completion of the trial, as well as testing of stored urine for measurement of hCG and detection of very early pregnancy losses, and karyotyping of the products of conception for assessment of aneuploidy of the losses.

PARTICIPANTS, SETTING, METHODS

Women aged 18-40 with a history of one to two prior losses and actively trying to conceive were randomized (n = 615 LDA and n = 613 placebo) at four clinical centers in the USA (2007-2011). Log-binomial regression was used to estimate risk ratios under the intent-to-treat approach.

MAIN RESULTS AND THE ROLE OF CHANCE

Daily LDA initiated preconception was not associated with clinically recognized pregnancy losses or implantation failures among women with proved fecundity and a history of one to two prior losses. Specifically, 1088 (88.6%) women completed the trial with 797 having an hCG detected pregnancy (64.9%). Overall there were 133 clinical losses (12.7% LDA versus 11.8% placebo, P = 0.71) and 55 implantation failures (5.2% LDA versus 4.9% placebo, P = 0.89). No differences were found in rate of euploid losses (RR 1.11, 95% confidence interval: 0.99, 1.26).

LIMITATIONS, REASONS FOR CAUTION

Generalizability of these findings is limited to women with a history of one to two prior losses, and may further be limited to women of white race with higher socioeconomic status as given the rigors of the study protocol participants tended to be white and have higher incomes and more education. We were also missing karyotype information on approximately one-third of the clinically recognized pregnancy losses, which may limit our power to detect effects on euploid losses, though detailed sensitivity analysis showed similar results.

WIDER IMPLICATIONS OF THE FINDINGS

Our data do not support the general use of LDA to decrease pregnancy loss and further demonstrate no increased risk of loss for women on LDA treatment.

STUDY FUNDING/COMPETING INTERESTS

This research was supported by the Intramural Research Program of the Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland (Contract Nos. HHSN267200603423, HHSN267200603424, HHSN267200603426). The authors have no conflicts of interest.

TRIAL REGISTRATION NUMBER

The trial was registered at ClinicalTrials.gov #NCT00467363.

TRIAL REGISTRATION DATE

27 April 2007.

DATE OF FIRST PATIENT'S ENROLLMENT

15 June 2007.

Aspirin and heparin in pregnancy

INTRODUCTION

A pro-coagulant state during pregnancy can be involved in the occurrence of gestational vascular complications (GVCs) and venous thromboembolism (VTE).

AREAS COVERED

Antithrombotic drugs are used to prevent GVCs and VTE. Aspirin is not efficacious to prevent recurrences in women with previous early loss, while it can prevent pre-eclampsia in some groups of women. Heparins are not effective in the prevention of early recurrent loss and there is uncertainty about their efficacy in women carrying inherited thrombophilias. They could be efficacious in the prevention of GVCs in carriers of inherited thrombophilias, as GVCs have heterogeneous causes, and future studies have to focus on more homogeneous groups of patients. Not enough data are available regarding prophylaxis with heparins to prevent pregnancy-related VTE, but an accurate risk stratification of women during pregnancy and puerperium is crucial for administering prophylaxis in moderate-/high-risk women. Aspirin does not improve live births after assisted reproductive technologies, while heparins increase the number of clinical pregnancies and live births.

EXPERT OPINION

Aspirin is efficacious in the prevention of GVCs in women at risk for pre-eclampsia and in those with antiphospholipid antibodies syndrome. Heparins could give benefit to women at risk for GVCs and/or pregnancy-related VTE.

Preconception low dose aspirin and time to pregnancy: findings from the effects of aspirin in gestation and reproduction randomized trial

OBJECTIVE

The objective was to determine the effect of preconception-initiated daily low-dose aspirin (LDA; 81 mg/day) treatment on time to pregnancy in women with a history of pregnancy loss.

DESIGN

This was a multicenter, block-randomized, double-blind, placebo-controlled trial. Participants were block-randomized by center and eligibility stratum.

SETTING

The study was conducted at four U.S.A. medical centers (2007-2012).

PARTICIPANTS

Participants women aged 18-40 years actively attempting pregnancy, stratified by eligibility criteria: the "original" stratum, women with one loss <20 weeks' gestation during the previous year; and the "expanded" stratum, women with one or two previous losses of any gestational age regardless of time since loss.

INTERVENTION

Daily LDA was compared with matching placebo for up to six menstrual cycles of attempting pregnancy.

MAIN OUTCOME MEASURE

Time to hCG detected pregnancy and clinically confirmed pregnancy, analyzed by intention-to-treat, was measured.

RESULTS

Of the 1228 women randomly assigned to LDA (n = 615) or placebo (n = 613), 410 (67%) women receiving LDA achieved pregnancy compared to 382 (63%) receiving placebo, corresponding to a fecundability odds ratio (FOR) of 1.14 (95% CI: 0.97, 1.33). Among women in the original stratum (n = 541), LDA was associated with increased fecundability compared to placebo (FOR: 1.28; 95%CI: 1.02, 1.62).

CONCLUSIONS

Preconception-initiated LDA treatment resulted in a nonsignificant increase in fecundability of 14% in women with a history of 1-2 pregnancy losses, and a significant increase of 28% in women with a history of only one pregnancy loss of <20 weeks' gestation in the preceding year. Preconception-initiated LDA may increase fecundability in certain women with a recent early pregnancy loss.

Heme oxygenase and the immune system in normal and pathological pregnancies

Normal pregnancy is an immunotolerant state. Many factors, including environmental, socioeconomic, genetic, and immunologic changes by infection and/or other causes of inflammation, may contribute to inter-individual differences resulting in a normal or pathologic pregnancy. In particular, imbalances in the immune system can cause many pregnancy-related diseases, such as infertility, abortions, pre-eclampsia, and preterm labor, which result in maternal/fetal death, prematurity, or small-for-gestational age newborns. New findings imply that myeloid regulatory cells and regulatory T cells (Tregs) may mediate immunotolerance during normal pregnancy. Effector T cells (Teffs) have, in contrast, been implicated to cause adverse pregnancy outcomes. Furthermore, feto-maternal tolerance affects the developing fetus. It has been shown that the Treg/Teff balance affects litter size and adoptive transfer of pregnancy-induced Tregs can prevent fetal rejection in the mouse. Heme oxygenase-1 (HO-1) has a protective role in many conditions through its anti-inflammatory, anti-apoptotic, antioxidative, and anti-proliferative actions. HO-1 is highly expressed in the placenta and plays a role in angiogenesis and placental vascular development and in regulating vascular tone in pregnancy. In addition, HO-1 is a major regulator of immune homeostasis by mediating crosstalk between innate and adaptive immune systems. Moreover, HO-1 can inhibit inflammation-induced phenotypic maturation of immune effector cells and pro-inflammatory cytokine secretion and promote anti-inflammatory cytokine production. HO-1 may also be associated with T-cell activation and can limit immune-based tissue injury by promoting Treg suppression of effector responses. Thus, HO-1 and its byproducts may protect against pregnancy complications by its immunomodulatory effects, and the regulation of HO-1 or its downstream effects has the potential to prevent or treat pregnancy complications and prematurity.

Ovarian hyperstimulation syndrome: pathophysiology, staging, prediction and prevention

OBJECTIVE

To identify, appraise and summarize the current evidence regarding the pathophysiology, staging, prediction and prevention of ovarian hyperstimulation syndrome (OHSS).

METHODS

Two comprehensive systematic reviews were carried out: one examined methods of predicting either high ovarian response or OHSS and the other examined interventions aimed at reducing the occurrence of OHSS. Additionally, we describe the related pathophysiology and staging criteria.

RESULTS

Seven studies examining methods of predicting OHSS and eight more examining methods of predicting high ovarian response to controlled ovarian stimulation were included. Current evidence shows that the best methods of predicting high response are antral follicle count and anti-Müllerian hormone levels, and that a high ovarian response (examined by the number of large follicles, estradiol concentration or the number of retrieved oocytes) is the best method of predicting the occurrence of OHSS. Ninety-seven randomized controlled trials examining the effect of several interventions for reducing the occurrence of OHSS were included. There was high-quality evidence that replacing human chorionic gonadotropin by gonadotropin-releasing hormone agonists or recombinant luteinizing hormone, and moderate-quality evidence that antagonist protocols, dopamine agonists and mild stimulation, reduce the occurrence of OHSS. The evidence for the effect of the other interventions was of low/very low quality. Additionally, we identified and described 12 different staging criteria.

CONCLUSIONS

There are useful predictive tools and several preventive interventions aimed at reducing the occurrence of OHSS. Acknowledging and understanding them are of crucial importance for planning the treatment of, and, ultimately, eliminating, OHSS while maintaining high pregnancy rates.

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.

Preconception low-dose aspirin and pregnancy outcomes: results from the EAGeR randomised trial

BACKGROUND

Preconception-initiated low-dose aspirin might positively affect pregnancy outcomes, but this possibility has not been adequately assessed. Our aim was to investigate whether low-dose aspirin improved livebirth rates in women with one to two previous pregnancy losses.

METHODS

In this multicentre, block-randomised, double-blind, placebo-controlled trial, women aged 18-40 years who were attempting to become pregnant were recruited from four medical centres in the USA. Participants were stratified by eligibility criteria--the original stratum was restricted to women with one loss at less than 20 weeks' gestation during the previous year, whereas the expanded stratum included women with one to two previous losses, with no restrictions on gestational age or time of loss. Women were block-randomised by centre and eligibility stratum in a 1:1 ratio. Preconception-initiated daily low-dose aspirin (81 mg per day) plus folic acid was compared with placebo plus folic acid for up to six menstrual cycles; for women who conceived, study treatment continued until 36 weeks' gestation. Participants, trial staff, and investigators were masked to the assigned treatment. The primary outcome was livebirth rate, which was analysed by intention to treat. The trial is registered with ClinicalTrials.gov, number NCT00467363.

FINDINGS

Overall, 1228 women were recruited and randomly assigned between June 15, 2007, and July 15, 2011, 1078 of whom completed the trial and were included in the analysis (535 in the low-dose aspirin group and 543 in the placebo group). 309 (58%) women in the low-dose aspirin group had livebirths, compared with 286 (53%) in the placebo group (p=0·0984; absolute difference in livebirth rate 5·09% [95% CI -0·84 to 11·02]). Pregnancy loss occurred in 68 (13%) women in the low-dose aspirin group, compared with 65 (12%) women in the placebo group (p=0·7812). In the original stratum, 151 (62%) of 242 women in the low-dose aspirin group had livebirths, compared with 133 (53%) of 250 in the placebo group (p=0·0446; absolute difference in livebirth rate 9·20% [0·51 to 17·89]). In the expanded stratum, 158 (54%) of 293 women in the low-dose aspirin group and 153 (52%) of 293 in the placebo group had livebirths (p=0·7406; absolute difference in livebirth rate 1·71% [-6·37 to 9·79]). Major adverse events were similar between treatment groups. Low-dose aspirin was associated with increased vaginal bleeding, but this adverse event was not associated with pregnancy loss.

INTERPRETATION

Preconception-initiated low-dose aspirin was not significantly associated with livebirth or pregnancy loss in women with one to two previous losses. However, higher livebirth rates were seen in women with a single documented loss at less than 20 weeks' gestation during the previous year. Low-dose aspirin is not recommended for the prevention of pregnancy loss.

FUNDING

Eunice Kennedy Shriver National Institute of Child Health and Human Development (US National Institutes of Health).

Clinical utility of antithrombotic prophylaxis in ART procedures: an Italian experience

BACKGROUND

The usefulness of antithrombotic prophylaxis in management of Assisted Reproductive Technologies (ART) is questionable.

OBJECTIVES

We prospectively examined the contribution of an antithrombotic prophylaxis in influencing clinical pregnancy and live-birth in an unselected cohort of women approaching ART.

PATIENTS/METHODS

1107 women with fertility problems and a valid indication for ART were recruited. Baseline and follow-up information of obstetric outcomes and antithrombotic treatment were collected.

RESULTS AND CONCLUSIONS

Median follow-up time was 34.5 months (range: 2-143). During the follow-up period, 595 (53.8%) women underwent ART (total 1234 cycles); 202 (33.9%) women achieved a pregnancy for a total of 255 clinical pregnancies. The concomitant use of LMWH and aspirin was significantly associated with a higher rate of clinical pregnancies (p: 0.003, OR: 4.9, 95% CI: 1.7-14.2). The pregnancy rate was also significantly increased by the use of LMWH alone (p: 0.005, OR: 2.6, 95% CI: 1.3-5.0). Carriership of inherited or acquired thrombophilia did not affect clinical outcomes of the ART. The efficacy of antithrombotic treatment was confirmed when the outcome " live-birth" was considered. Present data suggest a potential benefit of antithrombotic prophylaxis during ART in improving the number of live-births.

Embryo implantation: biology, evaluation, and enhancement

PURPOSE OF REVIEW

Implantation is an essential step in the development of a pregnancy, but often fails in humans. In assisted reproductive technologies, implantation failure continues to impair treatment outcomes, with distressing results for patients and physicians.

RECENT FINDINGS

Morphokinetics, comprehensive chromosome screening, and the analysis of embryo-derived products detectable in spent culture media offer new means of assessing embryo viability. However, all await validation in randomized controlled trials. Genomic, transcriptomic, and secretomic technologies are similarly being exploited to define specific biomarkers of endometrial receptivity with the aim of identifying novel therapeutic interventions. However, to date no single, clinically relevant molecular marker capable of indicating endometrial receptivity has been reported. Recent work continues to describe the key signalling pathways which result in acceptance or rejection of the implanting embryo. In-vitro studies have revealed that the decidualized endometrium plays an important role in natural embryo selection, which could change our understanding of the aetiology and treatment of reproductive failure.

SUMMARY

Recent developments in analytical techniques have initiated a search for biomarkers of embryo quality and endometrial receptivity, and in-vitro studies have revealed novel roles for the decidualized endometrium as a biosensor of embryo quality.

Could empirical low-dose-aspirin administration during IVF cycle affect both the oocytes and embryos quality via COX 1-2 activity inhibition?

PURPOSE

To compare qualitative and quantitative ovarian response in idiopathic infertile women treated with low-dose-aspirin (LDA) during in-vitro-fertilization (IVF) cycles (pl) versus untreated ones.

METHODS

We conducted an observational-cohort-study on normo-responders patients aged between 25 and 45,years referred to Assisted-Reproductive Unit --University of Padua--in order to evaluate the ovarian response effects (both qualitative and quantitative) after LDA administration. In detail we aim to assess if LDA administration could improve ovarian response, reducing the gonadotropin administration, and if its administration could increase the amount of follicles greater than 16 mm at pick-up, the amount and quality of oocytes retrieved, the amount and quality of embryos, the chance to achieve a pregnancy and to carry it on.

RESULTS

One hundred six LDA-treated patients (Group-A) and 100 not-treated ones (Group-B) were homogeneous for age and BMI. The Group-A, compared to Group-B, showed higher gonadotropin request, higher number of ovarian follicles at pick-up, more follicles bigger than 16 mm in diameter and more retrieved oocytes (despite higher number of immature and at germinal vesicle stage oocytes) but lower quality of obtained embryos. The comparison between two Groups in term of retrieved oocytes /number of follicles, mature oocytes/retrieved oocytes, fertilized oocytes/mature oocytes and good embryos quality/mature oocytes showed a strongly advantageous ratio for Group-B. For each considered outcome, we found a dose-related effect.

CONCLUSIONS

It is mandatory to define which patients could benefit from LDA administration and the adequate timing to administer it since the empirical administration could negatively affect both oocyte and embryo quality during IVF cycles.