Low-dose aspirin use does not improve in vitro fertilization outcomes in poor responders

Poor ovarian response classification systems in the clinical setting - time for an update?

PURPOSE OF REVIEW

Poor ovarian response (POR) remains a key challenge to the success of assisted reproductive technology. Here, we offer a comprehensive review of the two main classification systems for POR, discussing their promises and pitfalls, evaluating their performance, and exploring potential avenues for improving upon these definitions of POR.

RECENT FINDINGS

The Bologna criteria represented the first meaningful attempt to create a universal POR definition. Subsequently, the POSEIDON classification system was published to provide a more nuanced view of POR, classifying patients into four groups based on age and ovarian reserve markers. A recent study evaluated the likelihood of achieving at least one euploid embryo for transfer and found that, indeed, these classification systems are effective predictors of this outcome.While these criteria provide an effective counseling tool, several limitations - not considering underlying conditions, selecting somewhat arbitrary cutoffs, and evaluating the number of oocytes retrieved regardless of maturity - highlight the importance of improving upon these systems to create a more useful tool to more accurately predict ovarian response for clinical and research purposes.

SUMMARY

In the era of personalized medicine, it is time to reconsider whether diagnostic criteria for a continuous metric such as ovarian response should be based on meeting all-or-nothing thresholds for specific parameters.

Pregravid preparation of women with chronic endometritis in IVF cycles

OBJECTIVE

Aim: of our study was to improve the pregravid preparation of women with chronic endometritis to develop individual approaches to overcoming infertility, taking into account the state of endometrium.

PATIENTS AND METHODS

Materials and Methods: The study included 90 women (main group, n=90), 28 to 38 years with an anatomically normal uterus and chronic endometritis (CE). Patients were divided into 2 groups: group I - 45 women with CE who received conventional treatment; group II - 45 women with CE who received pregravid preparation by subendometrial injections of Platelet-Rich Plasma (PRP).

RESULTS

Results: At the first stage of study, the ART statistical reports from 2015 to 2022 were analyzed at the Medical Center of Reproductive Health ≪Damia≫, (Ivano-Frankivsk). Analysis of the vaginal flora parameters before treatment at the first stage revealed the presence of conditionally pathogenic flora in culture from the cervical canal (Candida albicans - 2.4%, Escherihia coli - 4.8%, Staphylococcus epidermidis - 6.2% Enterococcus faecalis - 6.9%), and was evidence of a possible recurrence of inflammation during gestation. In the age category, the groups of patients were homogeneous, with no significant differences by the level of AMH and the level of CD 138. Biochemical pregnancy be present in 20 patients (44.4%) of group I and 28 (62.2%) of group II. Fertility within a year after the end of therapy was restored with the proposed method of therapy in most women (51.1%), in the comparison group this number was 11.1% lower. Pregnancy rate between the groups (I and II) did not differ significantly. The number of live births in group II - 19 births (42.2%) - was 2 times higher than I group (9 (20.0%), P<0.05). The most common complication for women in the comparison groups was early pregnancy loss. Among 18 (40.0%) clinical pregnancies of group I, 8 women (17.8%) had early miscarriage, 1 ectopic pregnancy (2.2%), while in group II clinical pregnancy be present in 23 women (51.1%). The number of terminated pregnancies was two times lower than in the first group (8.9% vs. 17.8%, P<0.05).

CONCLUSION

Conclusions: Chronic endometritis is one of the main causes of pregnancy loss after in vitro fertilization. Patients of the second group were treated with the proposed method of subendometrial injections with Platelet-Rich Plasma (PRP), prepared from autologous blood, is an effective method of preparing the endometrium for embryo transfer and can increase the number of live births in patients with chronic endometritis.

Evidence for the effectiveness of immunologic therapies in women with subfertility and/or undergoing assisted reproduction

Implantation is a critical step in the establishment of a successful pregnancy, depending on a complex immune-endocrine dialogue between the developing embryo and maternal endometrium. Research suggests that altered immunity in the maternal decidua results in implantation impairment and failure. Immunomodulatory drugs have, thus, been widely used in assisted conception to aid embryo implantation, despite an absence of consensus on their effectiveness and safety. We conducted a systematic review and meta-analysis of interventional studies investigating the use of immunomodulators in women undergoing assisted reproduction. Evidence was uncertain of an effect for most of the included interventions, owing to heterogeneous findings and a paucity of high-quality studies. For certain patient subgroups, however, the use of specific immunomodulatory therapies may offer some benefit. There is a need for further large randomized controlled trials to corroborate these findings.

The effect of low-dose aspirin on the pregnancy rate in frozen-thawed embryo transfer cycles: A randomized clinical trial

Background

The results of previous studies on the effect of low-dose aspirin in frozen-thawed embryo transfer (FET) cycles are limited and controversial.

Objective

To evaluate the effect of low-dose aspirin on the clinical pregnancy in the FET cycles.

Materials and Methods

This study was performed as a randomized clinical trial from May 2018 to February 2019; 128 women who were candidates for the FET were randomly assigned to two groups receiving either 80 mg oral aspirin (n = 64) or no treatment. The primary outcome was clinical pregnancy rate and secondary outcome measures were the implantation rate, miscarriage rate, and endometrial thickness.

Results

The endometrial thickness was lower in patients who received aspirin in comparison to the control group. There were statistically significant differences between the two groups (p = 0.018). Chemical and clinical pregnancy rates and abortion rate was similar in the two groups and there was no statistically significant difference.

Conclusion

The administration of aspirin in FET cycles had no positive effect on the implantation and the chemical and clinical pregnancy rates, which is in accordance with current Cochrane review that does not recommend aspirin administration as a routine in assisted reproductive technology cycles.

High Prevalence of Sticky Platelet Syndrome in Patients with Infertility and Pregnancy Loss

Platelet hyperaggregability, known as sticky platelet syndrome (SPS), is a prothrombotic disorder that has been increasingly associated with pregnancy loss. In this retrospective study, we aimed to investigate the clinical and diagnostic relevance of SPS in 208 patients with infertility and unexplained pregnancy loss history. We studied 208 patients that had been referred to undergo a dose-dependent platelet aggregation response to adenosine diphosphate and epinephrine using light transmission aggregometry modified by Mammen during an 11-year period. Patients’ platelet aggregation response was compared with platelet function in 29 female healthy controls of fertile age with no previous history of pregnancy loss. We found a prevalence of SPS type II (33.2%) in 208 female patients with infertility and pregnancy loss. ∆-epinephrine-induced platelet aggregation in patients with SPS was significantly decreased (median 7% and range −21 to 43%) compared to patients without SPS (median 59%, range 7–88% and p < 0.0001) and healthy controls (median 57%, range 8–106% and p < 0.0001). The optimum SPS-diagnostic cutoff value for ∆-epinephrine aggregation was ≤32% (sensitivity 95.7%, specificity 95.2%). SPS patients with low-dose acetylsalicylic acid (ASA) therapy (n = 56) showed improved pregnancy outcome (32 pregnancies; live births n = 18 (56%)) compared to SPS patients without low-dose ASA (n = 13) (3 pregnancies; live births n = 1 (33%)). Our study demonstrates the clinical and diagnostic relevance of platelet hyperaggregation in women with infertility and pregnancy loss history. Further studies should investigate the potential of SPS as a novel decisional tool with both diagnostic and clinical implications in infertility and pregnancy loss.

Evaluation of the Second Follicular Wave Phenomenon in Natural Cycle Assisted Reproduction: A Key Option for Poor Responders through Luteal Phase Oocyte Retrieval

Background: Emergence of Luteal Phase Oocyte Retrieval (LuPOR) may revolutionize the practice regarding the time-sensitive nature of poor responders ascertaining a higher number of oocytes, in a shorter amount of time. This may be especially important in view of employing the approach of natural cycles for Poor Responders. We suggest the acronym LuPOR describing the clinical practice of luteal phase oocyte retrieval. The aim of the study is to offer insight regarding the identity of LuPOR, and highlight how this practice may improve management of the special subgroup of poor responders. Materials and Methods: The present retrospective observational clinical study includes the collection and statistical analysis of data from 136 poor responders who underwent follicular oocyte retrieval (FoPOR) and subsequent LuPOR in natural cycles, during their In Vitro Fertilization (IVF) treatment, from the time period of 2015 to 2018. All 136 participants were diagnosed with poor ovarian reserve (POR) according to Bologna criteria. The 272 cycles were categorized as follows: 136 natural cycles with only FoPORs (Control Group) and 136 natural cycles including both FoPORs and LuPORs. Results: Our primary results indicate no statistically significant differences with regards to the mean number of oocytes, the maturation status, and fertilization rate between FoPOR and LuPOR in natural cycles. Secondarily, we demonstrate a statistically significant higher yield of oocytes (2.50 ± 0.78 vs. 1.25 ± 0.53), better oocyte maturity status (1.93 ± 0.69 vs. 0.95 ± 0.59) and higher fertilization rate (1.31 ± 0.87 vs. 0.61 ± 0.60) in natural cycles including both FoPOR and LuPOR, when compared to cycles including only FoPOR. Conclusion: Our study may contribute towards the establishment of an efficient poor responders’ management through the natural cycle approach, paving a novel clinical practice and ascertaining the opportunity to employ oocytes and embryos originating from a luteal phase follicular wave.

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.

[Poor responders: How could we improve our results?]

OBJECTIVES

Finding an efficient treatment for poor responders still poses a tremendous challenge for assisted reproductive technology. In 2011, an international consensus has been reached in Bologna on how to standardize the definition of poor ovarian response (POR) in a simple and reproducible manner. This article provides an objective assessment of the different treatment options currently available.

METHODS

A search of the database PUBMED was carried out for studies published in English between October 2000 and April 2016.

RESULTS

There is no ideal protocol to manage poor responders even though the antagonist protocol seems to have an advantage of clinicians. This is thanks to better patient tolerance and reduced total dose of gonadotrophin as well as shorter time of stimulation. It seems that there is no benefit in increasing the gonadotrophin daily doses over 300IU nor using any specific type of gonadotrophin. Today, there is insufficient evidence to recommend any additional treatment for poor responders. Only dehydroepiandrosterone (DHEA) seems to increase embryonic quality and pregnancy rate, however further exploration and complementary prospective studies are necessary.

CONCLUSION

New treatment strategies such as "oocyte banking" or double stimulation during the same cycle, could provide new prospects in poor responders management.

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.

Poor ovarian reserve

Poor ovarian reserve (POR) is an important limiting factor for the success of any treatment modality for infertility. It indicates a reduction in quantity and quality of oocytes in women of reproductive age group. It may be age related as seen in advanced years of reproductive life or may occur in young women due to diverse etiological factors. Evaluating ovarian reserve and individualizing the therapeutic strategies are very important for optimizing the success rate. Majority or women with POR need to undergo in vitro fertilization to achieve pregnancy. However, pregnancy rate remains low despite a plethora of interventions and is associated with high pregnancy loss. Early detection and active management are essential to minimize the need for egg donation in these women.

Comparison of The Effectiveness of Clomiphene Citrate versus Letrozole in Mild IVF in Poor Prognosis Subfertile Women with Failed IVF Cycles

BACKGROUND

Our objective was to evaluate the effectiveness of clomiphene citrate (CC) vs. letrozole (L) plus human menopausal gonadotropin (hMG) in gonadotropin releasing hormone (GnRH) antagonist protocol in poor prognosis women with previous failed ovarian stimulation undergoing intracytoplasmic sperm injection (ICSI).

MATERIALS AND METHODS

This retrospective cohort study included cycles with CC and L plus hMG/GnRH antagonist protocols of 32 poor responders who had failed to have ideal follicles to be retrieved during oocyte pick-up (OPU) or embryo transfer (ET) at least for 2 previous in vitro fertilization (IVF) cycles with microdose flare protocol or GnRH antagonist protocol from January 2006 to December 2009. Main outcome measures were implantation, clinical pregnancy and live birth rates per cycle. Duration of stimulation, mean gonadotropin dose used, endometrial thickness, number of mature follicles, serum estradiol (E2) and progesterone (P) levels on the day of human chorionic gonadotropin (hCG) administration, number of retrieved oocytes and fertilization rates were also evaluated.

RESULTS

A total number of 42 cycles of 32 severe poor responders were evaluated. Total gonadotropin consumption was significantly lower (1491 ± 873 vs. 2808 ± 1581 IU, P=0.005) and mean E2 level on the day of hCG injection were significantly higher in CC group than L group (443.3 ± 255.2 vs. 255.4 ± 285.2 pg/mL, P=0.03). ET, overall pregnancy and live birth rates per cycle were significantly higher in CC than L protocol (27.2 vs. 15%, 13.6 vs. 0% and 4.5 vs. 0%, respectively, P<0.05).

CONCLUSION

Severe poor responders who had previously failed to respond to microdose or GnRH antagonist protocols may benefit from CC plus hMG/GnRH antagonist protocol despite high cancellation rate.

How to define, diagnose and treat poor responders? Responses from a worldwide survey of IVF clinics

Poor responders represent a significant percentage of couples treated in IVF units (10-24%), but the standard definition of poor responders remains uncertain and consequently optimal treatment options remain subjective and not evidence-based. In an attempt to provide uniformity on the definition, diagnosis and treatment of poor responders, a worldwide survey was conducted asking IVF professionals a set of questions on this complex topic. The survey was posted on www.IVF-worldwide.com, the largest and most comprehensive IVF-focused website for physicians and embryologists. A total of 196 centres replied, forming a panel of IVF units with a median of 400 cycles per year. The present study shows that the definition of poor responders is still subjective, and many practices do not use evidence-based treatment for this category of patients. Our hope is that by leveraging the great potential of the internet, future studies may provide immediate large-scale sampling to standardize both poor responder definition and treatment options.

Embryo quality in controlled ovarian stimulation for in vitro fertilization in young poor responders

This retrospective matched case control study was conducted to evaluate the effects of poor ovarian response in a group of young women (20-30 years) on embryos quality in controlled ovarian hyperstimulation (COH) for in vitro fertilization. Thirty-nine young patients with poor ovarian response (≤5 oocytes on retrieval) were enrolled and compared to age- and date-matched controls. Maximal Estradiol levels, number of oocytes aspirated, number of M2 oocytes and number of fertilized oocytes were significantly lower in the study group compared to controls. Implantation rate and rate of good quality embryos transferred of the study group and control were comparable (15.3 versus 16.3% and 62 versus 67.2%, respectively). Additionally, clinical pregnancy rate per transfer and delivery rate per transfer were also comparable (26.6 versus 35.8% and 23.3 versus 30.7%, respectively). The rate of cycles with no transfer, however, was 23.07% in the study group compared to zero cycles with no transfer in the control group. We conclude that young poor responders may still have reasonable proportion of good quality embryos when compared to controls. This results in comparable implantation rate and clinical pregnancy rate. Cycle transfer cancelation, however, represents a true barrier for achieving pregnancy.

Management of poor responders in IVF: is there anything new?

Despite the fact that in the last two decades an enormous number of papers on the topic of poor ovarian response have been published in the literature, so far it has been impossible to identify any efficient treatment to improve the ovarian response and the clinical outcome of this group of patients. The incidence of poor ovarian responders among infertile women has been estimated at 9–24% but according to recent reviews, it seems to have slightly increased. The limitation in quantifying the incidence of these patients among the infertile population is due to the difficulty of a clear definition in literature. A recent paper by the Bologna ESHRE working group on poor ovarian response has been the first real attempt to find a common definition. Current literature proposes new risk factors which could be the cause of a reduction in ovarian reserve, which also includes genetic factors. This represents the first necessary step towards finding applicable solutions for these patients. To date, there is a substantial lack of literature that identifies an ideal protocol for these patients. The use of the “Bologna criteria” and the introduction of long acting gonadotropin in clinical practice have given rise to new promising stimulation protocols for this group of patients.

Luteal phase support with estrogen in addition to progesterone increases pregnancy rates in in vitro fertilization cycles with poor response to gonadotropins

In this study, our objective was to determine the effect of adding estradiol hemihydrate (E2) to progestin (P) for luteal phase support on pregnancy outcome in in vitro fertilization (IVF) cycles with poor response to gonadotropins. Ninety-five women with poor ovarian response who underwent controlled ovarian hyperstimulation (COH) with gonadotropin releasing hormone (GnRH) agonist or GnRH antagonist plus gonadotropin protocol for IVF were prospectively randomized into three groups of luteal phase support after oocyte retrieval. Group 1 (n = 33) received only intravaginal progesterone gel (Crinone 8% gel). Group 2 (n = 27) and Group 3 (n = 35) received intravaginal progesterone plus oral 2 and 6 mg estradiol hemihydrate, respectively. Main outcome measures were overall and clinical pregnancy rates (PRs) per patient. Serum LH, E2 and P levels at 7th and 14th days of luteal phase were also measured. Overall and clinical PRs were significantly higher in 2 mg E2 + P than P-only group (44% versus 18% and 37% versus 12.1%, respectively). There were no statistically significant differences between 6 mg E2 + P versus P-only and 2 mg E2 + P versus 6 mg E2 + P groups regarding PRs. Addition of 2 mg/day E2 in addition to P for luteal support significantly increase overall and clinical PRs in cycles with poor response to gonadotropins after IVF.

DHEA supplementation may improve IVF outcome in poor responders: a proposed mechanism

OBJECTIVE

Dehydroepiandrosterone (DHEA) supplementation for poor responders may improve ovarian response and IVF treatment outcome. This study aimed to determine the mechanism of action of DHEA, and specifically, the stage of folliculogenesis influenced by DHEA.

STUDY DESIGN

This is a prospective, self-controlled study of poor responders to IVF treatment, comparing day 3 biochemical (anti-Mullerian hormone (AMH), inhibin B and FSH) and ultrasound (antral follicle count (AFC)) ovarian reserve markers and IVF treatment outcome before and after DHEA supplementation of at least 3 months duration.

RESULTS

Thirty-two women were included. Following DHEA, there was a significant increase in AFC (P=0.0003) without significant changes in the baseline biochemical parameters AMH, inhibin B, or FSH. The enhanced response comprised increased peak estradiol levels (P=0.0005), number of follicles >15 mm, oocytes, MII oocytes and embryos (P=0.004, P=0.00001, P=0.0004 and P=0.0006, respectively) and oocytes number/total FSH dose (P=0.0009). The proportion of cancelled cycles due to very poor response decreased significantly (P=0.02).

CONCLUSIONS

DHEA does not appear to exert influence via recruitment of pre-antral or very small antral follicles (no change in AMH and inhibin B) but rather by rescue from atresia of small antral follicles (increased AFC).

Aspirin for in vitro fertilisation

BACKGROUND

Aspirin is used to improve the outcome in women undergoing in vitro fertilisation despite inconsistent evidence of its efficacy. The most appropriate time to commence aspirin therapy and the length of treatment required are also still to be determined. This is an update of the review first published in 2007.

OBJECTIVES

To determine the effectiveness and safety of aspirin for improving the outcome of in vitro fertilisation and intracytoplasmic sperm injection treatment cycles.

SEARCH STRATEGY

We searched the Cochrane Menstrual Disorders and Subfertility Group Trials Register, Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library January 2011), MEDLINE (1966 to January 2011) and EMBASE (1980 to January 2011) databases. We used the research terms: "(aspirin OR acetylsalicylic acid) AND (in-vitro fertilisation OR intracytoplasmic sperm injection)", combined with the Cochrane Menstrual Disorders and Subfertility Group's search strategy, in order to identify randomised controlled trials on aspirin for women undergoing in vitro fertilisation.

SELECTION CRITERIA

Randomised controlled trials.

DATA COLLECTION AND ANALYSIS

Two authors independently selected studies to include in the review, extracted data and assessed trial quality.

MAIN RESULTS

The searches identified 13 trials which were eligible for inclusion in the review, including a total of 2653 participants. No significant differences were found between the treatment and control groups for any of the outcomes assessed. No significant differences were found in the meta-analysis of studies investigating the effect of aspirin compared with control on live birth rate (RR 0.91, 95% CI 0.72 to 1.15; three studies and 1053 participants), clinical pregnancy rate (RR 1.03, 95% CI 0.91 to 1.17; 10 studies and 2142 participants), ectopic and miscarriage rates (RR 1.86, 95% CI 0.75 to 4.63; RR 1.10, 95% CI 0.68 to 1.77) respectively (three and five studies involving 1135 and 1497 participants).

AUTHORS' CONCLUSIONS

Use of aspirin for women undergoing in vitro fertilisation cannot be recommended due to lack of evidence from the current trial data. Adequately powered trials are needed. It was proposed in the initial version of this review that a sample size of 350 women in each group would be required in order to demonstrate a 10% improvement from the use of aspirin, with 80% power at the 5% significance level. Until such evidence is available, this treatment can not be recommended.

[Cancellation of IVF-ET cycles: poor prognosis, poor responder, or variability of the response to controlled ovarian hyperstimulation? An analysis of 142 cancellations]

INTRODUCTION

This retrospective study aimed at analyzing IVF-ET management and outcome after cancellation of a first cycle for poor response.

PATIENTS AND METHOD

One hundred and forty-two infertile patients were included in this observational study. After an overall analysis on the outcome of the second IVF-ET attempt, a sub-analysis was performed according to the presence or the absence of poor prognostic criteria defined as mentioned: patient age superior to 38 years old, antral follicle count (3-9 mm in diameter) inferior to 10 on cycle day 3 and day 3 serum AMH and FSH levels less than 1 ng/mL and more than 10 IU/mL, respectively. Main outcome measures were the cancellation rates, pregnancy and live birth rates.

RESULTS

When a controlled ovarian stimulation was performed, patients with poor prognosis had higher cancellation rates (37.8% vs. 13.3%, P<0.004) and lower pregnancy and live birth rates (22.2% vs. 35.0%, P<0.05 and 11.1% vs. 26.1%, P<0.05, respectively) as compared to good prognosis women.

CONCLUSION

The relatively high cancellation rate in patients with poor prognosis raises the question of the use of IVF modified natural cycle in this group.

ESHRE consensus on the definition of 'poor response' to ovarian stimulation for in vitro fertilization: the Bologna criteria

The definition presented here represents the first realistic attempt by the scientific community to standardize the definition of poor ovarian response (POR) in a simple and reproducible manner. POR to ovarian stimulation usually indicates a reduction in follicular response, resulting in a reduced number of retrieved oocytes. It has been recognized that, in order to define the poor response in IVF, at least two of the following three features must be present: (i) advanced maternal age or any other risk factor for POR; (ii) a previous POR; and (iii) an abnormal ovarian reserve test (ORT). Two episodes of POR after maximal stimulation are sufficient to define a patient as poor responder in the absence of advanced maternal age or abnormal ORT. By definition, the term POR refers to the ovarian response, and therefore, one stimulated cycle is considered essential for the diagnosis of POR. However, patients of advanced age with an abnormal ORT may be classified as poor responders since both advanced age and an abnormal ORT may indicate reduced ovarian reserve and act as a surrogate of ovarian stimulation cycle outcome. In this case, the patients should be more properly defined as 'expected poor responder'. If this definition of POR is uniformly adapted as the 'minimal' criteria needed to select patients for future clinical trials, more homogeneous populations will be tested for any new protocols. Finally, by reducing bias caused by spurious POR definitions, it will be possible to compare results and to draw reliable conclusions.

Drug delivery for in vitro fertilization: rationale, current strategies and challenges

In vitro fertilization has experienced phenomenal progress in the last thirty years and awaits the additional refinement and enhancement of medication delivery systems. Opportunity exists for the novel delivery of gonadotropins, progesterone and other adjuvants. This review highlights the rationale for various medications, present delivery methods and introduces the status of novel ideas and possibilities.

Bibliography. Current world literature

This bibliography is compiled by clinicians from the journals listed at the end of this publication. It is based on literature entered into our database between 1 February 2008 and 31 January 2009 (articles are generally added to the database about two and a half months after publication). In addition, the bibliography contains every paper annotated by reviewers; these references were obtained from a variety of bibliographic databases and published between the beginning of the review period and the time of going to press. The bibliography has been grouped into topics that relate to the reviews in this issue.

Effects of low-dose aspirin in in-vitro fertilization

PURPOSE OF REVIEW

In theory, use of aspirin in IVF is based on its anti-inflammatory, vasodilatory, and platelet aggregation inhibition properties, which improve blood flow to a woman's implantation site. It is hypothesized that this effect on blood flow will improve success rates.

RECENT FINDINGS

Clinical studies investigating the use of low-dose aspirin (LDA) as an adjuvant therapy to IVF have produced conflicting results. The conflicting results have come as a consequence of the heterogeneous mixture of clinical trials with lack of adequate power. Even after multiple meta-analyses, differing estimates of effect were calculated as to whether aspirin should be used in conjunction with IVF.

SUMMARY

Conflicting results leave the question of the effects of LDA in IVF unanswered. More trials are required for analysis to have adequate statistical power and until then the data remain unclear. At this point, there are not enough data to show that aspirin has a beneficial effect on the outcomes of IVF, but absence of effect is not adequate grounds to overturn the current clinical practice for those using LDA in efforts aimed at achieving success with IVF.

Keeping clinicians in clinical research: the Clinical Research/Reproductive Scientist Training Program

In recent years the need for translational and clinical research has increased, whereas the number of physicians involved in clinical research has diminished. There is clearly a need for formalized academic training in the quantitative and methodologic principles of clinical research in reproductive medicine. The Clinical Research/Reproductive Scientist Training Program (CREST), a program supported by the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), the Clinical Research Training Program (CRTP) at Duke University, and the American Society for Reproductive Medicine (ASRM), meets this existing need. In addition, this program is specifically designed for physicians in private or academic clinical practice in reproductive medicine. Innovative programs such as CREST encourage the practicing physician to engage in clinical research while maintaining an active role in clinical practice. Participants in the program receive didactic on-line training from the CRTP and attend intensive weekend seminars at the National Institutes of Health (NIH) as well as CREST seminars at the annual meeting of the ASRM. Successful participants in the program receive a Certificate in Clinical Research from the CRTP. The program's goal is to provide practicing physicians with the tools and research credentials that will facilitate collaborations with investigators involved in large clinical trials.