Comparison of mild stimulation and conventional stimulation in ART outcome

Introduce an optimal method of ovarian stimulation in the polycystic ovarian syndrome affected: a randomized controlled trial

BACKGROUND

Currently, optimal method of ovarian stimulation (OS) to in-vitro fertilization (IVF) in the patients with polycystic ovarian syndrome (PCOS) is unknown. The present research aims to study the efficiency of minimal-OS method in treatment of infertile patients with PCOS and also the effect of gonadotropin type (recombinant FSH (r-FSH) vs. urinary Human menopausal gonadotropin (u-HMG)) on treatment cycles with GnRH-antagonist.

METHODS

In this randomized controlled trial, a total of 120 eligible patients were randomly allocated into four groups of OS to IVF: minimal-OS with r-FSH, minimal-OS with u-HMG, mild-OS with r-FSH and mild-OS with u-HMG. IVF outcomes of groups were analyzed statically.

RESULTS

The statistical analysis showed that there were significant differences among groups regarding stimulation duration (p < 0.0001), number of retrieved oocytes (p < 0.0001), number of obtained embryos (p < 0.0001). There were no statistically significant differences in fertilization rate (p = 0.289) and implantation rate (p = 0.757) among our participants. There were also significant differences among these four groups in terms of clinical pregnancy rate (/ET and /cycles) (p < 0.0001, p = 0.021, respectively) and live birth rate/cycles (p < 0.0001). Also cases of freeze all embryos due to prevention of ovarian hyper stimulation syndrome (OHSS) (p = 0.004).

CONCLUSIONS

On the basis of present results the minimal-OS with u-HMG may be one of optimal methods of control OS in the patients with PCOS in respect to serum levels of estradiol on the day of triggering final oocyte maturation, total dose of prescribed gonadotropin, the optimal number of oocytes and embryos obtained, rate of clinical pregnancy and the incidence of OHSS risk.

TRIAL REGISTRATION

NCT, NCT03876145. Registered 15/03/2019. Retrospectively registered, http://www.

CLINICALTRIAL

gov/ NCT03876145.

Effects of controlled ovarian stimulation regimens on top-quality blastocyst development and perinatal outcomes with the freeze-all strategy: A retrospective comparative study

OBJECTIVE

This study aimed to determine the effect of ovarian stimulation regimens on the top-quality blastocyst development rate and perinatal outcomes with the freeze-all strategy.

METHODS

A retrospective comparative cohort analysis of 149 in vitro fertilization (IVF) cycles using the freeze-all strategy was conducted. The IVF cycles were stimulated with either a gonadotropin-releasing hormone antagonist or clomiphene citrate along with gonadotropin based on the patient's serum anti-Müllerian hormone level. Oocyte retrieval, fertilization, and embryo culture were performed following standard procedures. All good-quality blastocysts were cryopreserved and used for frozen-thawed embryo transfer (FET) in subsequent cycles. The fertilization, blastulation, and top-quality blastocyst development rates were calculated. The perinatal outcomes of FET cycles, gestational period, and birth weight were assessed.

RESULTS

The main outcome of this study was the top-quality blastocyst development rate, and the secondary outcomes were perinatal parameters (e.g., gestational period and birth weight) between the stimulation regimens. Despite the higher number of usable-quality embryos in the antagonist group, the blastocyst development rate remained comparable (p=0.105). Similarly, perinatal outcomes were comparable in subsequent FET cycles (p=0.538).

CONCLUSION

These findings suggest that the choice between antagonist and clomiphene citrate with gonadotropin as stimulation in controlled ovarian stimulation regimens may not affect the top-quality blastocyst development rate. The IVF outcomes (e.g., clinical pregnancy, miscarriage, and live birth rates) remained unaffected in subsequent FET cycles. Unlike fresh embryo transfer, the birth weight and gestational length were not associated with prior controlled ovarian stimulation regimens when the freeze-all strategy was used.

Severe ovarian hyperstimulation syndrome induced by clomiphene: a case report

This article reported a rare case of severe ovarian hyperstimulation syndrome (OHSS) following oral clomiphene. The patient was instructed to take clomiphene on the 5th day of menstruation, 50 mg daily for 5 days, without any medical examination or laboratory tests before administration of clomiphene. The treatment outcome was ideal by conservative treatment. This reminded that full assessment and risk prediction should be performed before the prescription of clomiphene. And clomiphene should be used only when indicated. What's more, high risk factors of the particular patient should be taken into full consideration.

Does the additional use of clomiphene citrate or letrozole for in vitro fertilization deserve more attention?

BACKGROUND

Adding clomiphene citrate (CC) and/or letrozole (LE) to in vitro fertilization (IVF) cycles for mild ovarian stimulation is a general approach. Although lots of researches have demonstrated partial benefits of the strategy, all-around effects of oral medications remained deficient. This paper aims to assess whether an addition of oral medication will result in considerable outcomes on T-Gn (total dose of gonadotropin), Gn days, total retrieved ova, high quality embryos, blastocyst number, ovarian hyperstimulation syndrome (OHSS) rate, clinical pregnancy rate and cumulative pregnancy rate, even if it was not conventional mild/minimal stimulations.

RESULTS

Participants were categorized to three diverse populations as high responders, normal responders and poor responders according to basal antral follicle count. T-Gn in patients treated with CC/LE distinctly decreased from 2496.96 IU/d to 1827.68 IU/d, from 2860.28 IU/d to 2119.99 IU/d, and from 3182.15 IU/d to 1802.84 IU/d, respectively. For high ovary responders and normal responders, the OHSS incidence rate also declined from 29.2 to 4.3% (P < 0.001) and from 1.1 to 0.0% (P = 0.090). Other, there was no statistical difference with respect to the T-retrieved ova (total retrieved ova), high quality embryos, cultured blastocyst and blastocyst number in high responders. For normal responders and poor ovary responders, T-Gn, Gn days, T-retrieved ova, high quality embryos, cultured blastocyst and blastocysts number in oral medications group all apparently decreased. Clinical pregnancy rate per fresh cycle of poor responders with prior oral medications was significantly decreased (25.7% vs. 50.8%, P = 0.005), and no significant differences in high responders and normal responders were expressed (52.5% vs. 44.2%, P = 0.310; 51.9% vs. 42.4%, P = 0.163) between two groups of participants. The numbers of cumulative pregnancy rates were lower in the conventional group compared to the add group for high (75.90% versus 81.03%, P = 0.279), normal (62.69% versus 71.36%, P = 0.016) and poor (39.74% versus 68.21%, P < 0.001) responders.

CONCLUSIONS

The addition of CC/LE to the ovulation induction during IVF has certain efficacy in terms of low cost, low OHSS incidence. CC/LE deserves more recommendations as a responsible strategy in high responders due to advantageous pregnancy outcomes. For normal responders, the strategy needs to be considered with more comprehensive factors.

Mild versus conventional ovarian stimulation for IVF in poor, normal and hyper-responders: a systematic review and meta-analysis

BACKGROUND

Mild ovarian stimulation has emerged as an alternative to conventional IVF with the advantages of being more patient-friendly and less expensive. Inadequate data on pregnancy outcomes and concerns about the cycle cancellation rate (CCR) have prevented mild, or low-dose, IVF from gaining wide acceptance.

OBJECTIVE AND RATIONALE

To evaluate parallel-group randomised controlled trials (RCTs) on IVF where comparisons were made between a mild (≤150 IU daily dose) and conventional stimulation in terms of clinical outcomes and cost-effectiveness in patients described as poor, normal and non-polycystic ovary syndrome (PCOS) hyper-responders to IVF.

SEARCH METHODS

Searches with no language restrictions were performed using Medline, Embase, Cochrane central, Pre-Medicine from January 1990 until April 2020, using pre-specified search terms. References of included studies were hand-searched as well as advance access articles to key journals. Only parallel-group RCTs that used ≤150 IU daily dose of gonadotrophin as mild-dose IVF (MD-IVF) and compared with a higher conventional dose (CD-IVF) were included. Studies were grouped under poor, normal or hyper-responders as described by the authors in their inclusion criteria. Women with PCOS were excluded in the hyper-responder group. The risk of bias was assessed as per Cochrane Handbook for the included studies. The quality of evidence (QoE) was assessed according to the GRADE system. PRISMA guidance was followed for review methodology.

OUTCOMES

A total of 31 RCTs were included in the analysis: 15 in the poor, 14 in the normal and 2 in the hyper-responder group. Live birth rates (LBRs) per randomisation were similar following use of MD-IVF in poor (relative risk (RR) 0.91 (CI 0.68, 1.22)), normal (RR 0.88 (CI 0.69, 1.12)) and hyper-responders (RR 0.98 (CI 0.79, 1.22)) when compared to CD-IVF. QoE was moderate. Cumulative LBRs (5 RCTs, n = 2037) also were similar in all three patient types (RR 0.96 (CI 0.86 1.07) (moderate QoE). Risk of ovarian hyperstimulation syndrome was significantly less with MD-IVF than CD-IVF in both normal (RR 0.22 (CI 0.10, 0.50)) and hyper-responders (RR 0.47 (CI 0.31, 0.72)), with moderate QoE. The CCRs were comparable in poor (RR 1.33 (CI 0.96, 1.85)) and hyper-responders (RR 1.31 (CI 0.98, 1.77)) but increased with MD-IVF among normal responders (RR 2.08 (CI 1.38, 3.14)); all low to very low QoE. Although fewer oocytes were retrieved and fewer embryos created with MD-IVF, the proportion of high-grade embryos was similar in all three population types (low QoE). Compared to CD-IVF, MD-IVF was associated with less gonadotrophin use and lower cost.

WIDER IMPLICATIONS

This updated review provides reassurance on using MD-IVF not only for the LBR per cycle but also for the cumulative LBR, with moderate QoE. With risks identified with ‘freeze-all’ strategies, it may be time to recommend mild-dose ovarian stimulation for IVF for all categories of women i.e. hyper, poor and normal responders to IVF.

Controlled Ovarian Stimulation Protocols Alter Endometrial Histomorphology and Gene Expression Profiles

Although it is well appreciated that ovarian stimulation protocols for in vitro fertilization (IVF) alter endometrial receptivity, the precise cellular mechanisms are not known. To gain insights into potential mechanisms by which different ovarian stimulation protocols alter the endometrium, we compared histologic and gene expression profiles of endometrium from women undergoing conventional ovarian stimulation for IVF (C-IVF) with those undergoing minimal stimulation with clomiphene citrate (MS-IVF). Sixteen women undergoing MS-IVF (n = 8) or C-IVF (n = 8) were recruited for endometrial biopsy at the time of oocyte retrieval. Endometrial glands were large, tortuous, and secretory with C-IVF but small and undifferentiated with MS-IVF. Whereas RNA sequencing did not reveal changes in estrogen receptor or its co-regulators or classic proliferation associated genes in MS-IVF, together with immunohistochemistry, Wnt signaling was disrupted in endometrium from MS-IVF cycles with significant upregulation of Wnt inhibitors. Secreted frizzled-related protein 1 (sFRP1) was increased fourfold (p < 0.01), and sFRP4 was upregulated sixfold (p < 0.01) relative to C-IVF. Further these proteins were localized to subepithelial endometrial stroma. These data indicate that MS-IVF protocols with CC do not seem to impact endometrial estrogen signaling as much as would be expected from the reported antiestrogenic properties of CC. Rather, the findings of this study highlight Wnt signaling as a major factor for endometrial development during IVF cycles.

Use of Clomiphene Citrate in minimal stimulation in vitro fertilization negatively impacts endometrial thickness: an argument for a freeze-all approach

Objective

Minimal stimulation IVF is a treatment option that uses clomiphene citrate (CC). We sought to evaluate how CC impacts endometrial thickness during minimal stimulation IVF cycles.

Methods

We retrospectively analyzed a cohort of 230 cycles in 119 poor ovarian response patients. The IVF cycles were studied in three groups: 130 minimal stimulation cycles, 29 mild stimulation cycles, and 30 conventional high dose gonadotropin releasing hormone (GnRH) antagonist cycles. Thirty-three minimal stimulation IVF patients had 41 frozen embryo transfers (FET) which allowed us to study whether the CC effects were prolonged.

Results

Endometrial thickness in the minimal stimulation group was significantly lower than the mild and conventional stimulation groups (7.3±2.2mm versus 11.4±3.3mm versus 12.9±3.8mm, respectively, p<0.0001). In patients who underwent minimal stimulation IVF followed by FET, significantly thicker endometrial thickness was achieved during their FET cycles as compared to their minimal stimulation cycles (7.95±2.1mm versus 10.3±1.8mm, p<0.0001).

Conclusion

We concluded that endometrial thickness is impacted during minimal stimulation IVF cycles. Since negative effects on endometrial thickness are not observed in the patients’ subsequent FET cycle, a freeze-all approach is justified to mitigate adverse endometrial effects of CC in minimal stimulation IVF cycles.

Recent advances in oncofertility care worldwide and in Japan

BACKGROUND

Oncofertility is a crucial facet of cancer supportive care. The publication of guidelines for the cryopreservation of oocytes and ovarian tissue is becoming increasingly prevalent in Japan and an updated overview is necessary.

METHODS

In order to provide an updated overview of oncofertility care, original research and review articles were searched from the PubMed database and compared in order to present clinical care in Japan.

RESULTS

In Western countries, various methods for ovarian stimulation, such as the combined use of aromatase inhibitors and random-start protocols, have been reported. Although ovarian tissue cryopreservation, mainly performed via the slow-freezing method, also has yielded >100 live births, the optimal indications and procedures for the auto-transplantation of cryopreserved tissue have been under investigation. In Japan, however, vitrification is prevalent for ovarian tissue cryopreservation, although its efficacy has not yet been established. The quality of network systems for providing oncofertility care in Japan varies greatly, based on the region.

CONCLUSION

There remain many issues in the optimization of oncofertility care in Japan. Along with the regional oncofertility networks, the creation of "oncofertility navigators" from healthcare providers who are familiar with oncofertility, such as nurses, psychologists, and embryologists, could be useful for supplementing oncofertility care coordination, overcoming the issues in individual regions.

GnRH antagonist versus long agonist protocols in IVF: a systematic review and meta-analysis accounting for patient type

BACKGROUND

Most reviews of IVF ovarian stimulation protocols have insufficiently accounted for various patient populations, such as ovulatory women, women with polycystic ovary syndrome (PCOS) or women with poor ovarian response, and have included studies in which the agonist or antagonist was not the only variable between the compared study arms.

OBJECTIVE AND RATIONALE

The aim of the current study was to compare GnRH antagonist protocols versus standard long agonist protocols in couples undergoing IVF or ICSI, while accounting for various patient populations and treatment schedules.

SEARCH METHODS

The Cochrane Menstrual Disorders and Subfertility Review Group specialized register of controlled trials and Pubmed and Embase databases were searched from inception until June 2016. Eligible trials were those that compared GnRH antagonist protocols and standard long GnRH agonist protocols in couples undergoing IVF or ICSI. The primary outcome was ongoing pregnancy rate. Secondary outcomes were: live birth rate, clinical pregnancy rate, number of oocytes retrieved and safety with regard to ovarian hyperstimulation syndrome (OHSS). Separate comparisons were performed for the general IVF population, women with PCOS and women with poor ovarian response. Pre-planned subgroup analyses were performed for various antagonist treatment schedules.

OUTCOMES

We included 50 studies. Of these, 34 studies reported on general IVF patients, 10 studies reported on PCOS patients and 6 studies reported on poor responders. In general IVF patients, ongoing pregnancy rate was significantly lower in the antagonist group compared with the agonist group (RR 0.89, 95% CI 0.82-0.96). In women with PCOS and in women with poor ovarian response, there was no evidence of a difference in ongoing pregnancy between the antagonist and agonist groups (RR 0.97, 95% CI 0.84-1.11 and RR 0.87, 95% CI 0.65-1.17, respectively). Subgroup analyses for various antagonist treatment schedules compared to the long protocol GnRH agonist showed a significantly lower ongoing pregnancy rate when the oral hormonal programming pill (OHP) pretreatment was combined with a flexible protocol (RR 0.74, 95% CI 0.59-0.91) while without OHP, the RR was 0.84, 95% CI 0.71-1.0. Subgroup analysis for the fixed antagonist schedule demonstrated no evidence of a significant difference with or without OHP (RR 0.94, 95% CI 0.79-1.12 and RR 0.94, 95% CI 0.83-1.05, respectively). Antagonists resulted in significantly lower OHSS rates both in the general IVF patients and in women with PCOS (RR 0.63, 95% CI 0.50-0.81 and RR 0.53, 95% CI 0.30-0.95, respectively). No data on OHSS was available from trials in poor responders.

WIDER IMPLICATIONS

In a general IVF population, GnRH antagonists are associated with lower ongoing pregnancy rates when compared to long protocol agonists, but also with lower OHSS rates. Within this population, antagonist treatment prevents one case of OHSS in 40 patients but results in one less ongoing pregnancy out of every 28 women treated. Thus standard use of the long GnRH agonist treatment is perhaps still the approach of choice for prevention of premature luteinization. In couples with PCOS and poor responders, GnRH antagonists do not seem to compromise ongoing pregnancy rates and are associated with less OHSS and therefore could be considered as standard treatment.

Hypertensive Disorders in Pregnant Women Receiving Fertility Treatments

Hypertensive disorders (HDs) as the most prevalent medical problem during pregnancy, predispose the patient to a lot of comorbidities and may even cause maternal or fetal death. The rate of infertility has been increasing in recent decades. So, we collected and summarized data about the co-existence of these two entities and found that HDs are somewhat more common in women receiving fertility treatments regardless of pathophysiologic correlation of infer- tility and hypertension or older age and chance of multiple pregnancies.

Oral medications including clomiphene citrate or aromatase inhibitors with gonadotropins for controlled ovarian stimulation in women undergoing in vitro fertilisation

BACKGROUND

Gonadotropins are the most commonly used medications for controlled ovarian stimulation in in vitro fertilisation (IVF). However, they are expensive and invasive, and are associated with the risk of ovarian hyperstimulation syndrome (OHSS). Recent calls for more patient-friendly regimens have led to growing interest in the use of clomiphene citrate (CC) and aromatase inhibitors with or without gonadotropins to reduce the burden of hormonal injections. It is currently unknown whether regimens using CC or aromatase inhibitors such as letrozole (Ltz) are as effective as gonadotropins alone.

OBJECTIVES

To determine the effectiveness and safety of regimens including oral induction medication (such as clomiphene citrate or letrozole) versus gonadotropin-only regimens for controlled ovarian stimulation in IVF or intracytoplasmic sperm injection (ICSI) treatment.

SEARCH METHODS

We searched the following databases: Cochrane Gynaecology and Fertility Group Specialised Register (searched January 2017), the Cochrane Central Register of Controlled Trials (CENTRAL CRSO), MEDLINE (1946 to January 2017), Embase (1980 to January 2017), and reference lists of relevant articles. We also searched trials registries ClinicalTrials.gov (clinicaltrials.gov/) and the World Health Organization International Clinical Trials Registry Platform (www.who.int/trialsearch/Default.aspx). We handsearched relevant conference proceedings.

SELECTION CRITERIA

We included randomized controlled trials (RCTs). The primary outcomes were live-birth rate (LBR) and OHSS.

DATA COLLECTION AND ANALYSIS

Three review authors independently assessed trial eligibility and risk of bias. We calculated risk ratios (RR) and Peto odds ratio (OR) with 95% confidence intervals (CIs) for dichotomous outcomes and mean differences (MD) for continuous outcomes. We analyzed the general population of women undergoing IVF treatment and (as a separate analysis) women identified as poor responders. We assessed the overall quality of the evidence using the GRADE approach.

MAIN RESULTS

We included 27 studies in the updated review. Most of the new trials in the updated review included poor responders and evaluated Ltz protocols. We could perform meta-analysis with data from 22 studies including a total of 3599 participants. The quality of the evidence for different comparisons ranged from low to moderate. The main limitations in the quality of the evidence were risk of bias associated with poor reporting of study methods, and imprecision.In the general population of women undergoing IVF, it is unclear whether CC or Ltz used with or without gonadotropins compared to use of gonadotropins along with gonadotropin-releasing hormone (GnRH) agonists or antagonists resulted in a difference in live birth (RR 0.92, 95% CI 0.66 to 1.27, 4 RCTs, n = 493, I2 = 0%, low-quality evidence) or clinical pregnancy rate (RR 1.00, 95% CI 0.86 to 1.16, 12 RCTs, n = 1998, I2 = 3%, moderate-quality evidence). This means that for a typical clinic with 23% LBR using a GnRH agonist regimen, switching to CC or Ltz protocols would be expected to result in LBRs between 15% and 30%. Clomiphene citrate or Ltz protocols were associated with a reduction in the incidence of OHSS (Peto OR 0.21, 95% CI 0.11 to 0.41, 5 RCTs, n = 1067, I2 = 0%, low-quality evidence). This means that for a typical clinic with 6% prevalence of OHSS associated with a GnRH regimen, switching to CC or Ltz protocols would be expected to reduce the incidence to between 0.5% and 2.5%. We found evidence of an increase in cycle cancellation rate with the CC protocol compared to gonadotropins in GnRH protocols (RR 1.87, 95% CI 1.43 to 2.45, 9 RCTs, n = 1784, I2 = 61%, low-quality evidence). There was moderate quality evidence of a decrease in the mean number of ampoules used,) and mean number of oocytes collected with CC with or without gonadotropins compared to the gonadotropins in GnRH agonist protocols, though data were too heterogeneous to pool.Similarly, in the poor-responder population, it is unclear whether there was any difference in rates of live birth (RR 1.16, 95% CI 0.49 to 2.79, 2 RCTs, n = 357, I2 = 38%, low-quality evidence) or clinical pregnancy (RR 0.85, 95% CI 0.64 to 1.12, 8 RCTs, n = 1462, I2 = 0%, low-quality evidence) following CC or Ltz with or without gonadotropin versus gonadotropin and GnRH protocol. This means that for a typical clinic with a 5% LBR in the poor responders using a GnRH protocol, switching to CC or Ltz protocols would be expected to yield LBRs between 2% to 14%. There was low quality evidence that the CC or Ltz protocols were associated with an increase in the cycle cancellation rate (RR 1.46, 95% CI 1.18 to 1.81, 10 RCTs, n = 1601, I2 = 64%) and moderate quality evidence of a decrease in the mean number of gonadotropin ampoules used and the mean number of oocytes collected, though data were too heterogeneous to pool. The adverse effects of these protocols were poorly reported. In addition, data on foetal abnormalities following use of CC or Ltz protocols are lacking.

AUTHORS' CONCLUSIONS

We found no conclusive evidence indicating that clomiphene citrate or letrozole with or without gonadotropins differed from gonadotropins in GnRH agonist or antagonist protocols with respect to their effects on live-birth or pregnancy rates, either in the general population of women undergoing IVF treatment or in women who were poor responders. Use of clomiphene or letrozole led to a reduction in the amount of gonadotropins required and the incidence of OHSS. However, use of clomiphene citrate or letrozole may be associated with a significant increase in the incidence of cycle cancellations, as well as reductions in the mean number of oocytes retrieved in both the general IVF population and the poor responders. Larger, high-quality randomized trials are needed to reach a firm conclusion before they are adopted into routine clinical practice.

Mild stimulation for in vitro fertilization

It has been proven that the use of high gonadotropin dose does not necessarily improve the final outcome of IVF. Mild ovarian stimulation is based on the principle of optimal utilization of competent oocytes/embryos and endometrial receptivity. There is growing evidence that the pregnancy or live birth rates with mild-stimulation protocols are comparable to those with conventional IVF; the cumulative pregnancy outcome has been shown to be no different, despite having fewer numbers of oocytes or embryos available with milder ovarian stimulation. Although equally effective, mild-stimulation IVF is associated with a greater safety profile, in terms of the incidence of ovarian hyperstimulation syndrome and venous thromboembolism. It is also found to be better tolerated by patients and less expensive. Emerging research evidence may lead to widespread acceptance of mild IVF, by both patients and IVF providers, and make IVF more accessible to women and couples worldwide.

In vitro fertilization treatments with the use of clomiphene citrate or letrozole

There has been increasing interest in combining the oral agents clomiphene citrate (CC) and letrozole with gonadotropins in IVF: for poor responders to reduce the amount of gonadotropins used, and in normal responders to reduce the incidence of ovarian hyperstimulation (OHSS). In normal responders, mild stimulation with the use of CC and gonadotropins was found to decrease the number of oocytes retrieved and result in good pregnancy rates, but in most studies the cumulative pregnancy rate was lower compared with conventional ovarian stimulation when frozen embryo transfers were considered. Coadministration of letrozole and gonadotropins has mainly been used in patients with breast cancer to prevent the massive elevation of serum E₂ concentrations with the use of standard controlled ovarian hyperstimulation. CC and letrozole have both been used with gonadotropins in poor responders and have been shown to reduce the amount of gonadotropin used without reducing the pregnancy rate. Letrozole use with gonadotropins in IVF cycles may increase endometrial receptivity by increasing integrin expression in the endometrium and by lowering estrogen concentrations to more physiologic levels.

Effectiveness of mild ovarian stimulation versus GnRH agonist protocol in women undergoing assisted reproductive technology: a meta-analysis

OBJECTIVE

our meta-analysis was conducted to evaluate the effectiveness of the mild ovulation induction protocol using CC/gonadotropin/GnRH antagonist compared to the conventional GnRH agonist protocol in women undergoing ART.

METHOD

Six electronic databases were searched from their date of establishment until August 2016. Outcomes in our analysis were calculated in terms of relative risk (RR) and weighted mean differences (WMD) and standard mean differences (SMD) with 95% confidence intervals (CI) using random effect models or fixed effect models.

RESULTS

Six prospective controlled clinical trials with 1543 women comparing the clinical impacts of the two protocols were included. The synthesized results suggested a significant reduction in the quantity of gonadotropins (SMD: -1.96, 95% CI: -2.28 to 1.64, I² = 78.5%), the incidence of OHSS (RR: 0.16, 95% CI 0.03-0.86, I² = 0%) and an increase in the cycle cancelation rate (RR: 1.46, 95% CI 1.05-2.03, I² = 89.4%). While no evidence of statistically significant differences between the groups existed in the other clinical outcomes.

CONCLUSION

This study suggested that the probable benefits of the mild protocol, including its less costs and safer process without reducing the overall IVF treatment success rates, seemed to make it a better treatment option. Larger sample prospective trials evaluating live birth, clinical pregnancy, OHSS, multiple pregnancy incidence and so on were desired to establish.

Clomiphene citrate and letrozole to reduce follicle-stimulating hormone consumption during ovarian stimulation: systematic review and meta-analysis

OBJECTIVE

To assess the available evidence comparing effectiveness of ovarian stimulation (OS) using clomiphene citrate (CC) and/or letrozole (LTZ) to reduce follicle-stimulating hormone (FSH) consumption compared with standard OS.

METHODS

We performed a systematic review and meta-analysis of randomized controlled trials that compared reproductive outcomes following in-vitro fertilization. We searched 11 electronic databases and hand-searched the reference lists of included studies and related reviews. We stratified the results, separating studies according to the oral agent used (CC or LTZ) and the characteristics of the included women (expected poor ovarian response or other women). When combining the results of the included studies, we assessed the relative risk (RR) for live birth, clinical pregnancy, miscarriage and cycle cancelation, the Peto odds ratio (OR) for ovarian hyperstimulation syndrome (OHSS) and mean difference (MD) for the number of oocytes retrieved and FSH consumption.

RESULTS

A total of 22 studies were included in the review. Considering women with expected poor ovarian response, the available evidence suggested that using CC to reduce FSH consumption during OS provided similar rates of live birth (RR, 0.9 (95% CI, 0.6-1.2), moderate-quality evidence) and clinical pregnancy (RR, 1.0 (95% CI, 0.8-1.4), moderate-quality evidence); the use of LTZ did not cause a relevant change in the number of oocytes retrieved (MD, -0.4 (95% CI, -0.9 to 0.1), high-quality evidence). Considering the studies evaluating other women, the available evidence suggested that using CC to reduce FSH consumption during OS reduced the number of oocytes retrieved (MD, -4.6 (95% CI, -6.1 to -3.0), high-quality evidence) and risk of OHSS (Peto OR, 0.2 (95% CI, 0.1-0.3), moderate-quality evidence), while results were similar for rates of live birth (RR, 0.9 (95% CI, 0.7-1.1), moderate-quality evidence) and clinical pregnancy (RR, 1.0 (95% CI, 0.8-1.1), high-quality evidence). The quality of the evidence was low or very low for other outcomes.

CONCLUSION

The use of CC to reduce FSH consumption in women with expected poor ovarian response has the advantage of providing similar reproductive outcomes with reduced costs. For the other women, the use of CC for reducing FSH consumption has the additional advantage of reducing OHSS, but also reduces the total number of oocytes retrieved. More studies are needed to evaluate the effect of LTZ for the same purpose. Future studies should focus on cumulative pregnancy per oocyte retrieval, patient dissatisfaction and agreement to repeat the cycle if not pregnant, which are important outcomes for clinical decisions. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

Management of ovarian stimulation for IVF: narrative review of evidence provided for World Health Organization guidance

In this paper, a review of evidence provided to the World Health Organization (WHO) guideline development, who prepare global guidance on the management of ovarian stimulation for women undergoing IVF, is presented. The purpose of ovarian stimulation is to facilitate retrieval of multiple oocytes during a single IVF cycle. Availability of multiple oocytes compensates for inefficiencies in subsequent stages of the cycle, which include oocyte maturation, IVF, embryo culture, embryo transfer, and implantation. Multiple embryos can be transferred in most women, and spare embryos can be frozen to allow for future chances of pregnancy without the need for repeated ovarian stimulation and oocyte retrieval. Our evidence synthesis team addressed 10 clinical questions on management of ovarian stimulation for IVF, prepared a narrative review of the evidence and drafted recommendations to be considered through WHO guideline development processes. Our main outcome measures were live birth, clinical pregnancy, and ovarian hyperstimulation syndrome.

Prevention and treatment of moderate and severe ovarian hyperstimulation syndrome: a guideline

Ovarian hyperstimulation syndrome (OHSS) is an uncommon but serious complication associated with assisted reproductive technology (ART). This systematic review aims to identify who is at high risk, how to prevent OHSS, and the treatment for existing OHSS.

GnRH antagonist rescue protocol combined with cabergoline versus cabergoline alone in the prevention of ovarian hyperstimulation syndrome: a randomized controlled trial

Background

The aim of this study was to compare the efficacy of antagonist rescue protocol (replacing GnRH agonist with GnRH antagonist and reducing the dose of gonadotropins) combined with cabergoline versus cabergoline alone in the prevention of ovarian hyperstimulation syndrome (OHSS) in patients pretreated with GnRH agonist long protocol who were at high risk for OHSS.

Methods

Two hundred and thirty six patients were randomized in a 1:1 ratio to the cabergoline group or the antagonist rescue combined with cabergoline group. Both groups received oral cabergoline (0.5 mg/day) for eight days beginning on the day of HCG administration. In the antagonist rescue combined with cabergoline group, when the leading follicle reached 16 mm, GnRH agonist (triptorelin) was replaced with GnRH antagonist (cetrorelix acetate) and the dose of HP-uFSH was reduced to 75 IU/day. HCG (5,000 IU/I.M) was administered when the serum estradiol level dropped below 3500 pg/ml. The study was open label and the outcome assessors (laboratory staff and the doctor who performed oocyte retrieval) were blind to treatment allocation.

Results

The incidence of moderate/severe OHSS was significantly lower in the antagonist rescue combined with cabergoline group [5.08 % Vs 13.56 %, P value =0.025, OR = 0.342, 95 % CI, 0.129–0.906]. Four cycles were cancelled in the cabergoline group. There were no significant differences between the groups with respect to the number of retrieved oocytes, metaphase II oocytes, high quality embryos and fertilization rate. Moreover, the implantation and pregnancy rates were comparable between both groups.

Conclusion

GnRH antagonist rescue protocol combined with cabergoline is more effective than cabergoline alone in the prevention of OHSS.

Trial registration

Clinical trial.gov (NCT02461875).

Gonadotrophin-releasing hormone antagonists for assisted reproductive technology

BACKGROUND

Gonadotrophin-releasing hormone (GnRH) antagonists can be used to prevent a luteinizing hormone (LH) surge during controlled ovarian hyperstimulation (COH) without the hypo-oestrogenic side-effects, flare-up, or long down-regulation period associated with agonists. The antagonists directly and rapidly inhibit gonadotrophin release within several hours through competitive binding to pituitary GnRH receptors. This property allows their use at any time during the follicular phase. Several different regimens have been described including multiple-dose fixed (0.25 mg daily from day six to seven of stimulation), multiple-dose flexible (0.25 mg daily when leading follicle is 14 to 15 mm), and single-dose (single administration of 3 mg on day 7 to 8 of stimulation) protocols, with or without the addition of an oral contraceptive pill. Further, women receiving antagonists have been shown to have a lower incidence of ovarian hyperstimulation syndrome (OHSS). Assuming comparable clinical outcomes for the antagonist and agonist protocols, these benefits would justify a change from the standard long agonist protocol to antagonist regimens. This is an update of a Cochrane review first published in 2001, and previously updated in 2006 and 2011.

OBJECTIVES

To evaluate the effectiveness and safety of gonadotrophin-releasing hormone (GnRH) antagonists compared with the standard long protocol of GnRH agonists for controlled ovarian hyperstimulation in assisted conception cycles.

SEARCH METHODS

We searched the Cochrane Menstrual Disorders and Subfertility Group Trials Register (searched from inception to May 2015), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library, inception to 28 April 2015), Ovid MEDLINE (1966 to 28 April 2015), EMBASE (1980 to 28 April 2015), PsycINFO (1806 to 28 April 2015), CINAHL (to 28 April 2015) and trial registers to 28 April 2015, and handsearched bibliographies of relevant publications and reviews, and abstracts of major scientific meetings, for example the European Society of Human Reproduction and Embryology (ESHRE) and American Society for Reproductive Medicine (ASRM). We contacted the authors of eligible studies for missing or unpublished data. The evidence is current to 28 April 2015.

SELECTION CRITERIA

Two review authors independently screened the relevant citations for randomised controlled trials (RCTs) comparing different GnRH agonist versus GnRH antagonist protocols in women undergoing in vitro fertilisation (IVF) or intracytoplasmic sperm injection (ICSI).

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trial eligibility and risk of bias, and extracted the data. The primary review outcomes were live birth and ovarian hyperstimulation syndrome (OHSS). Other adverse effects (miscarriage and cycle cancellation) were secondary outcomes. We combined data to calculate pooled odds ratios (ORs) and 95% confidence intervals (CIs). Statistical heterogeneity was assessed using the I(2) statistic. We assessed the overall quality of the evidence for each comparison using GRADE methods.

MAIN RESULTS

We included 73 RCTs, with 12,212 participants, comparing GnRH antagonist to long-course GnRH agonist protocols. The quality of the evidence was moderate: limitations were poor reporting of study methods.Live birthThere was no conclusive evidence of a difference in live birth rate between GnRH antagonist and long course GnRH agonist (OR 1.02, 95% CI 0.85 to 1.23; 12 RCTs, n = 2303, I(2)= 27%, moderate quality evidence). The evidence suggested that if the chance of live birth following GnRH agonist is assumed to be 29%, the chance following GnRH antagonist would be between 25% and 33%.OHSSGnRH antagonist was associated with lower incidence of any grade of OHSS than GnRH agonist (OR 0.61, 95% C 0.51 to 0.72; 36 RCTs, n = 7944, I(2) = 31%, moderate quality evidence). The evidence suggested that if the risk of OHSS following GnRH agonist is assumed to be 11%, the risk following GnRH antagonist would be between 6% and 9%.Other adverse effectsThere was no evidence of a difference in miscarriage rate per woman randomised between GnRH antagonist group and GnRH agonist group (OR 1.04, 95% CI 0.82 to 1.30; 33 RCTs, n = 7022, I(2) = 0%, moderate quality evidence).With respect to cycle cancellation, GnRH antagonist was associated with a lower incidence of cycle cancellation due to high risk of OHSS (OR 0.47, 95% CI 0.32 to 0.69; 19 RCTs, n = 4256, I(2) = 0%). However cycle cancellation due to poor ovarian response was higher in women who received GnRH antagonist than those who were treated with GnRH agonist (OR 1.32, 95% CI 1.06 to 1.65; 25 RCTs, n = 5230, I(2) = 68%; moderate quality evidence).

AUTHORS' CONCLUSIONS

There is moderate quality evidence that the use of GnRH antagonist compared with long-course GnRH agonist protocols is associated with a substantial reduction in OHSS without reducing the likelihood of achieving live birth.

The association of serum estradiol level with outcomes of clomiphene citrate/human menopausal gonadotropin ovarian stimulation for in vitro fertilization and embryo transfer

BACKGROUND

The purpose of this study was to test the hypothesis that estradiol (E2) level on day 3 may be associated with in vitro fertilization (IVF) outcomes.

METHODS

The records of patients who received clomiphene citrate 100 mg/day plus human menopausal gonadotropin 150 IU/day from day 3 and received frozen-thawed embryo transfers were reviewed. Patients were divided into three groups: group A (E2 ≤30 pg/ml), group B (30< E2 ≤50 pg/ml), and group C (E2 >50 pg/ml). A total of 1080 cycles from 941 patients were included.

RESULTS

The number of eggs and MII oocytes were less in group C than group A (both, P = 0.001). The embryo implantation (P = 0.006) and clinical pregnancy rates (P = 0.036) were lower in group C than group B, and the rates were similar between group A and B.

CONCLUSION

Maintaining the serum E2 level from 30 to 50 pg/ml may result in a higher clinical pregnancy rate in IVF cycles.

Prevention of Ovarian Hyperstimulation Syndrome: A Review

The following review aims to examine the available evidence to guide best practice in preventing ovarian hyperstimulation syndrome (OHSS). As it stands, there is no single method to completely prevent OHSS. There seems to be a benefit, however, in categorizing women based on their risk of OHSS and individualizing treatments to curtail their chances of developing the syndrome. At present, both Anti-Müllerian Hormone and the antral follicle count seem to be promising in this regard. Both available and upcoming therapies are also reviewed to give a broad perspective to clinicians with regard to management options. At present, we recommend the use of a "step-up" regimen for ovulation induction, adjunct metformin utilization, utilizing a GnRH agonist as an ovulation trigger, and cabergoline usage. A summary of recommendations is also made available for ease of clinical application. In addition, areas for potential research are also identified where relevant.

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.

Comparison of GnRH agonist, GnRH antagonist, and GnRH antagonist mild protocol of controlled ovarian hyperstimulation in good prognosis patients

The reports on how to stimulate the ovaries for oocyte retrieval in good prognosis patients are contradictory and often favor one type of controlled ovarian hyperstimulation (COH). For this reason, we retrospectively analyzed data from IVF/ICSI cycles carried out at our IVF Unit in good prognosis patients (aged <38 years, first and second attempts of IVF/ICSI, more than 3 oocytes retrieved) to elucidate which type of COH is optimal at our condition. The included patients were undergoing COH using GnRH agonist, GnRH antagonist or GnRH antagonist mild protocol in combination with gonadotrophins. We found significant differences in the average number of retrieved oocytes, immature oocytes, fertilized oocytes, embryos, transferred embryos, embryos frozen per cycle, and cycles with embryo freezing between studied COH protocols. Although there were no differences in live birth rate (LBR), miscarriages, and ectopic pregnancies between compared protocols, pregnancy rate was significantly higher in GnRH antagonist mild protocol in comparison with both GnRH antagonist and GnRH agonist protocols and cumulative LBR per cycle was significantly higher in GnRH antagonist mild protocol in comparison to GnRH agonist protocol. Our data show that GnRH antagonist mild protocol of COH could be the best method of choice in good prognosis patients.

Mild ovarian stimulation for in vitro fertilization: are we ready to change? A meta-analysis

OBJECTIVE

To compare the efficacy of mild ovarian stimulation versus conventional stimulation in in vitro fertilization (IVF).

DESIGN

Meta-analysis.

SEARCH STRATEGY

A systemic literature search was carried out for prospective randomised clinical trials. We electronically searched using PubMed, Medline and Embase for all the studies published from 1990 to December 2011.

INTERVENTIONS

Mild ovarian stimulation IVF that uses lower doses and/or shorter duration of gonadotrophins in GnRH antagonist co-treated cycle compared with conventional stimulation IVF.

MAIN OUTCOME MEASURES

Live birth rates per started cycle and ongoing pregnancy rates per started cycle of IVF.

RESULTS

On live birth rate, there was a significant difference in favour of the conventional stimulation [70/444 (15.7%) mild vs. 78/325 (24%) conventional] (OR 0.59, CI 0.41-0.85, p = 0.004). Similar findings were observed in the ongoing pregnancy data [140/696 (20%) mild vs. 144/547 (26%) in favour of conventional stimulation] (OR 0.72, CI 0.55-0.93, p = 0.01). The sub-analysis of two studies showed a statistically significant reduction of hyperstimulation syndrome in favour of the mild stimulation (OR 0.27, CI 0.11-0.66).

CONCLUSION

This analysis presents strong evidence in favour of conventional stimulation IVF, which therefore should currently be considered a treatment of choice for patients requiring IVF treatment.

Clomiphene combined with gonadotropins and GnRH antagonist versus conventional controlled ovarian hyperstimulation without clomiphene in women undergoing assisted reproductive techniques: systematic review and meta-analysis

PURPOSE

To compare the effectiveness and safety of controlled ovarian hyperstimulation (COH) using clomiphene citrate associated with gonadotropin and GnRH antagonist (CC + Ant) versus conventional COH without clomiphene citrate (Non-CC) for women undergoing assisted reproductive techniques (ART).

METHODS

Systematic review and meta-analysis of randomized controlled-trials comparing CC + Ant versus non-CC. The last search was performed in Apr 13 2012. The following outcomes were retrieved from included trials and compared between CC + Ant versus non-CC: live birth, clinical pregnancy, ovarian hyperstimulation syndrome (OHSS), miscarriage, multiple pregnancy, endometrial thickness, total oocytes retrieved, MII oocytes retrieved, total gonadotropin used, and duration of COH.

RESULTS

Seven trials (702 participants) were included. There was no significant difference in live birth (55/182 = 30.2 % vs. 47/181 = 26.0 %, p = 0.26, CC + Ant vs. non-CC, respectively), clinical pregnancy (98/346 = 28.3 % vs. 84/356 = 23.6 %, p = 0.12), miscarriage (6/35 = 17.1 % vs. 7/32 = 21.9 %, p = 0.42), endometrial thickness, and on the number of oocytes retrieved. There was a significant reduction in OHSS (1/216 = 0.5 % vs. 9/217 = 4.1 %, p = 0.01), consumption of gonadotropins, and duration of COH.

CONCLUSIONS

Compared to non-CC, CC + Ant is likely to reduce the risk of OHSS, medication costs, and the duration of COH without evidence of effect on live birth and clinical pregnancy. More trials are still needed to improve the quality of the evidence. Future studies should evaluate women with PCOS or at increased risk of OHSS, quality of life, satisfaction with the treatment, total cost per live birth, and frequency of congenital anomalies.

Clomiphene citrate in combination with gonadotropins for controlled ovarian stimulation in women undergoing in vitro fertilization

BACKGROUND

Gonadotropins are the most commonly used medication for controlled ovarian stimulation in in vitro fertilization (IVF). However, they are expensive, invasive and are associated with risk of ovarian hyperstimulation syndrome (OHSS). With recent calls for patient friendly IVF, there has been an interest in the use of clomiphene citrate with or without gonadotropins to reduce the burden of injections. However, it is not known whether regimens using clomiphene are at least as effective as gonadotropins alone.

OBJECTIVES

To determine whether clomiphene citrate with gonadotropins (with or without mid-cycle antagonist) is more effective than gonadotropins with gonadotropin-releasing hormone (GnRH) agonists for controlled ovarian stimulation in IVF or intracytoplasmic sperm injection (ICSI) treatment.

SEARCH METHODS

Cochrane Menstrual Disorders and Subfertility Group Trials Register (searched March 2012), Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2012, first quarter), MEDLINE (1970 to March 2012), EMBASE (1985 to Mar 2012) and reference lists of articles. Relevant conference proceedings were handsearched.

SELECTION CRITERIA

Randomised controlled trials (RCT) were included. Live birth rate (LBR) per woman was the primary outcome.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed the eligibility and quality of trials

MAIN RESULTS

Fourteen studies were included in the review. Meta-analysis could be performed with the data of 12 included studies, with a total of 2536 participants. There was no evidence that clomiphene along with gonadotropins for IVF, with or without mid-cycle GnRH antagonist, differed from gonadotropins alone in GnRH agonist protocols in terms of live births (5 RCTs, 1079 women; OR 0.93, 95% CI 0.69 to1.24) or clinical pregnancy (11 RCTs, 1864 women; OR 1.07, 95% CI 0.85 to1.33). This means that for a typical clinic with 23% LBR using a GnRH agonist regimen, switching to clomiphene protocols would be expected to result in LBRs between 16% and 26%. There was a significant reduction in the incidence of OHSS (5 RCTs, 1559 women; OR 0.23, 95% CI 0.10 to 0.52). This means that for a typical clinic with 3.5% prevalence of OHSS using a GnRH agonist regimen, switching to clomiphene citrate protocols would be expected to reduce the incidence to between 0.8% and 1.8%. The trials included in this review were very old and outcomes such as live births, multiple pregnancy, OHSS and miscarriages have not been reported by most studies.

AUTHORS' CONCLUSIONS

There was no evidence to indicate that clomiphene with gonadotropins (with or without GnRH antagonist) differed significantly from gonadotropins in GnRH agonist protocols for women undergoing IVF treatment, in terms of live births or pregnancy rates. Meanwhile, use of clomiphene led to a reduction in the incidence of OHSS. However, these results were based on data from a small number of underpowered randomised trials with few participants. Hence there was insufficient evidence to recommend use of clomiphene citrate in routine IVF practice. Larger trials with adequate power are required.

Gonadotrophin-releasing hormone antagonists for assisted reproductive technology

BACKGROUND

Gonadotrophin-releasing hormone (GnRH) antagonists can be used to prevent a luteinizing hormone (LH) surge during controlled ovarian hyperstimulation (COH) without the hypo-estrogenic side-effects, flare-up, or long down-regulation period associated with agonists. The antagonists directly and rapidly inhibit gonadotropin release within several hours through competitive binding to pituitary GnRH receptors. This property allows their use at any time during the follicular phase. Several different regimes have been described including multiple-dose fixed (0.25 mg daily from day six to seven of stimulation), multiple-dose flexible (0.25 mg daily when leading follicle is 14 to 15 mm), and single-dose (single administration of 3 mg on day 7 to 8 of stimulation) protocols, with or without the addition of an oral contraceptive pill. Further, women receiving antagonists have been shown to have a lower incidence of ovarian hyperstimulation syndrome (OHSS). Assuming comparable clinical outcomes for the antagonist and agonist protocols, these benefits would justify a change from the standard long agonist protocol to antagonist regimens. This is an update of a Cochrane review first published in 2001, and previously updated in 2006.

OBJECTIVES

To evaluate the effectiveness and safety of gonadotrophin-releasing hormone (GnRH) antagonists with the standard long protocol of GnRH agonists for controlled ovarian hyperstimulation in assisted conception cycle

SEARCH STRATEGY

We performed electronic searches of major databases, for example Cochrane Menstrual Disorders and Subfertility Group Specialised Register, CENTRAL, MEDLINE, EMBASE (from 1987 to April 2010); and handsearched bibliographies of relevant publications and reviews, and abstracts of major scientific meetings, for example the European Society of Human Reproduction and Embryology (ESHRE) and American Society for Reproductive Medicine (ASRM). A date limited search of Cochrane Menstrual Disorders and Subfertility Group Specialised Register, CENTRAL from April 2010 to April 2011 was run. Eighteen studies have been entered into the Classification pending references section of this update. These studies will be appraised for inclusion or exclusion in the next update of this review, due April 2012.

SELECTION CRITERIA

Two review authors independently screened the relevant citations for randomised controlled trials (RCTs) comparing different agonist versus antagonist protocols in women undergoing IVF or ICSI.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trial risk of bias and extracted data. If relevant data were missing or unclear, the authors were contacted for clarification.

MAIN RESULTS

Forty-five RCTs (n = 7511) comparing the antagonist to the long agonist protocols fulfilled the inclusion criteria. There was no evidence of a statistically significant difference in rates of live-births (9 RCTs; odds ratio (OR) 0.86, 95% CI 0.69 to 1.08) or ongoing pregnancy (28 RCTs; OR 0.87, 95% CI 0.77 to 1.00). There was a statistically significant lower incidence of OHSS in the GnRH antagonist group (29 RCTs; OR 0.43, 95% CI 0.33 to 0.57).

AUTHORS' CONCLUSIONS

The use of antagonist compared with long GnRH agonist protocols was associated with a large reduction in OHSS and there was no evidence of a difference in live-birth rates.

Milder is better? Advantages and disadvantages of "mild" ovarian stimulation for human in vitro fertilization

In the last decades, several steps have been made aiming at rendering human IVF more successful on one side, more tolerable on the other side. The "mild" ovarian stimulation approach, in which a lower-than-average dose of exogenous gonadotropins is given and gonadotropin treatment is started from day 2 to 7 of the cycle, represents a significant step toward a more patient's friendly IVF. However, a clear view of its virtues and defects is still lacking, because only a few prospective randomized trials comparing "mild" vs. conventional stimulation exist, and they do not consider some important aspects, such as, e.g., thawing cycles. This review gives a complete panorama of the "mild" stimulation philosophy, showing its advantages vs. conventional ovarian stimulation, but also discussing its disadvantages. Both patients with a normal ovarian responsiveness to exogenous gonadotropins and women with a poor ovarian reserve are considered. Overall, we conclude that the level of evidence supporting the use of "mild" stimulation protocols is still rather poor, and further, properly powered prospective studies about "mild" treatment regimens are required.