A randomized, single-blind, prospective trial comparing three different gonadotropin doses with or without addition of letrozole during ovulation stimulation in patients with poor ovarian response

Letrozole co-treatment in an antagonist protocol for overweight women undergoing IVF treatment: a retrospective study

BACKGROUND

Overweight women undergoing IVF treatment have lower success rates. Letrozole, an aromatase inhibitor, has been used as an adjunct for IVF treatment, but its specific effects in overweight women have not been investigated. This study was to explore the effects of letrozole co-treatment in an antagonist protocol for overweight infertile women undergoing IVF treatment.

METHODS

This retrospective cohort study included overweight infertile women who underwent IVF/ICSI treatment and fresh embryo transfer (ET), with or without letrozole co-treatment in an antagonist protocol, from 2007 to 2021 at Shanghai Ninth People's Hospital (Shanghai, China). A total of 704 overweight infertile women were included: 585 women were in the antagonist group, and 119 women were in the letrozole co-treatment group. The primary outcome was the live birth rate after fresh ET. Propensity score-based patient-matching was employed to balance the covariates between the groups. Multivariate logistic regression analysis was also performed to estimate odds ratio (OR) and 95% confidence interval (CI) for association of letrozole co-treatment and the live birth outcome.

RESULTS

Letrozole co-treatment induced significant changes in hormonal profile on the trigger day. The letrozole group exhibited a decrease in the total number of follicles compared to the antagonist group, but a higher proportion of large follicles at oocyte retrieval (P < 0.05). The quantity and quality of embryos were comparable between the two groups (P > 0.05). The letrozole co-treatment group had a significantly higher live birth rate than the control group (38.7% vs. 22.6%, P = 0.026). With multivariate logistic regression analysis, letrozole co-treatment was associated with higher odds of live birth after adjusting for potential confounding factors (adjusted OR = 2.00, 95% CI = 1.17-3.39, P = 0.011). Letrozole presented no significant associations with obstetrical or neonatal complications (P > 0.05).

CONCLUSION

Letrozole co-treatment in an antagonist protocol may offer potential benefits for overweight infertile women undergoing IVF treatment. Further research is warranted to validate these findings and explore the broader implications for letrozole co-treatment.

The Efficacy of Letrozole Co-Treatment in an Antagonist Protocol for Women with Polycystic Ovary Syndrome Undergoing IVF: A Retrospective Study

Objective

Our objective was to investigate the efficacy of letrozole co-treatment in an antagonist protocol for infertile women with polycystic ovary syndrome (PCOS).

Patients and Methods

This retrospective cohort study included infertile women with PCOS undergoing IVF/ICSI with and without letrozole co-treatment in an antagonist protocol from 2007-2021 at Shanghai Ninth People's Hospital (Shanghai, China). A total of 1559 participants were enrolled, with 1227 women in the antagonist group and 332 women in the letrozole co-treatment group. Propensity score-based patient-matching model was conducted to balance covariates between the groups. The primary outcome was the number of retrieved oocytes, with secondary outcomes including endocrine parameters, ovarian stimulation outcomes, pregnancy outcomes, and obstetrical and neonatal complications.

Results

Letrozole co-treatment induced significant changes in hormonal regulation, increased the percentage of large follicles, and resulted in fewer retrieved oocytes (P < 0.05). However, there was no negative impact on the number of usable embryos or good-quality embryos (P > 0.05). The live birth rates following fresh embryo transfer were comparable between the letrozole and control groups (single embryo transfer: 28.9% vs 29.7%, P > 0.05; double embryo transfer: 37.3% vs 45.6%, P > 0.05). Additionally, there were no significant differences between the two groups in the live birth rate per patient after frozen embryo transfer and the cumulative live birth rate (P > 0.05). No significant differences in obstetrical and neonatal complications were observed between the groups (P > 0.05).

Conclusion

The addition of letrozole to the antagonist protocol for women with PCOS undergoing IVF induces a higher percentage of large follicles during oocyte retrieval, while reducing the overall number of retrieved oocytes. Moreover, the use of letrozole demonstrates comparable clinical outcomes following embryo transfers. These findings highlight the potential application of letrozole in an antagonist protocol for women with PCOS.

Letrozole cotreatment progestin-primed ovarian stimulation in women undergoing controlled ovarian stimulation for in vitro fertilization

AIM

To investigate the impact of letrozole cotreatment progestin-primed ovarian stimulation (PPOS) (Le PPOS) in controlled ovarian stimulation (COS) and the pregnancy outcomes in frozen-thawed embryo transfer cycles.

METHODS

This retrospective cohort study included women who underwent in vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI). A total of 2575 cycles were included (1675 in the Le PPOS group and 900 in the PPOS group). The primary outcome was the clinical pregnancy rates. The secondary outcome was the live birth rates.

RESULTS

In this study, propensity score matching (PSM) was performed to create a perfect match of 379 patients in each group. After matching, the numbers of oocytes retrieved, mature oocytes, fertilization, and clinical pregnancy rates were more favorable in the Le PPOS group than in the PPOS group (all p < 0.05). The multivariable analysis showed that the clinical pregnancy rate was higher in the Le PPOS than in the PPOS group (odds ratio = 1.46, 95% confidence interval: 1.05-2.04, p = 0.024) after adjusting for potentially confounding factors (age, anti-Müllerian hormone levels, antral follicular count, the type of embryo transferred, number of transferred embryos, body mass index, and follicular stimulating hormone and estradiol levels on starting day).

CONCLUSIONS

This retrospective study with a limited sample size suggests that the Le PPOS protocol might be an alternative to the PPOS protocol in women undergoing COS and could lead to better pregnancy outcomes. The results should be confirmed using a formal randomized controlled trial.

Individualised gonadotropin dose selection using markers of ovarian reserve for women undergoing in vitro fertilisation plus intracytoplasmic sperm injection (IVF/ICSI)

BACKGROUND

During a stimulated cycle of in vitro fertilisation or intracytoplasmic sperm injection (IVF/ICSI), women receive daily doses of gonadotropin follicle-stimulating hormone (FSH) to induce multifollicular development in the ovaries. A normal response to stimulation (e.g. retrieval of 5 to 15 oocytes) is considered desirable. Generally, the number of eggs retrieved is associated with the dose of FSH. Both hyper-response and poor response are associated with an increased chance of cycle cancellation. In hyper-response, this is due to increased risk of ovarian hyperstimulation syndrome (OHSS), while poor response cycles are cancelled because the quantity and quality of oocytes is expected to be low. Clinicians often individualise the FSH dose using patient characteristics predictive of ovarian response. Traditionally, this meant women's age, but increasingly, clinicians use various ovarian reserve tests (ORTs). These include basal FSH (bFSH), antral follicle count (AFC), and anti-Müllerian hormone (AMH). It is unclear whether individualising FSH dose improves clinical outcomes. This review updates the 2018 version.

OBJECTIVES

To assess the effects of individualised gonadotropin dose selection using markers of ovarian reserve in women undergoing IVF/ICSI.

SEARCH METHODS

We searched the Cochrane Gynaecology and Fertility Group Specialised Register of controlled trials, CENTRAL, MEDLINE, Embase, and two trial registers in February 2023.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) that compared (a) different doses of FSH in women with a defined ORT profile (i.e. predicted low, normal, or high responders based on AMH, AFC, and/or bFSH) or (b) an individualised dosing strategy (based on at least one ORT measure) versus uniform dosing or a different individualised dosing algorithm.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methodological procedures. Primary outcomes were live birth/ongoing pregnancy and severe OHSS.

MAIN RESULTS

We included 26 studies, involving 8520 women (6 new studies added to 20 studies included in the previous version). We treated RCTs with multiple comparisons as separate trials for the purpose of this review. Meta-analysis was limited due to clinical heterogeneity. Evidence certainty ranged from very low to low, with the main limitations being imprecision and risk of bias associated with lack of blinding. Direct dose comparisons according to predicted response in women Due to differences in dose comparisons, caution is required when interpreting the RCTs in predicted low responders. All evidence was low or very low certainty. Effect estimates were very imprecise, and increased FSH dosing may or may not have an impact on rates of live birth/ongoing pregnancy, OHSS, and clinical pregnancy. Similarly, in predicted normal responders (10 studies, 4 comparisons), higher doses may or may not impact the probability of live birth/ongoing pregnancy (e.g. 200 versus 100 international units (IU): odds ratio (OR) 0.88, 95% confidence interval (CI) 0.57 to 1.36; I2 = 0%; 2 studies, 522 women) or clinical pregnancy. Results were imprecise, and a small benefit or harm remains possible. There were too few events for the OHSS outcome to enable inferences. In predicted high responders, lower doses may or may not affect live birth/ongoing pregnancy (OR 0.98, 95% CI 0.66 to 1.46; 1 study, 521 women), severe OHSS, and clinical pregnancy. It is also unclear whether lower doses reduce moderate or severe OHSS (Peto OR 2.31, 95% CI 0.80 to 6.67; 1 study, 521 participants). ORT-algorithm studies Eight trials compared an ORT-based algorithm to a non-ORT control group. It is unclear whether live birth/ongoing pregnancy and clinical pregnancy are increased using an ORT-based algorithm (live birth/ongoing pregnancy: OR 1.12, 95% CI 0.98 to 1.29; I2 = 30%; 7 studies, 4400 women; clinical pregnancy: OR 1.04, 95% CI 0.91 to 1.18; I2 = 18%; 7 studies, 4400 women; low-certainty evidence). However, ORT algorithms may reduce moderate or severe OHSS (Peto OR 0.60, 95% CI 0.42 to 0.84; I2 = 0%; 7 studies, 4400 women; low-certainty evidence). There was insufficient evidence to determine whether the groups differed in rates of severe OHSS (Peto OR 0.74, 95% CI 0.42 to 1.28; I2 = 0%; 5 studies, 2724 women; low-certainty evidence). Our findings suggest that if the chance of live birth with a standard starting dose is 25%, the chance with ORT-based dosing would be between 25% and 31%. If the chance of moderate or severe OHSS with a standard starting dose is 5%, the chance with ORT-based dosing would be between 2% and 5%. These results should be treated cautiously due to heterogeneity in the algorithms: some algorithms appear to be more effective than others.

AUTHORS' CONCLUSIONS

We did not find that tailoring the FSH dose in any particular ORT population (low, normal, high ORT) affected live birth/ongoing pregnancy rates, but we could not rule out differences, due to sample size limitations. Low-certainty evidence suggests that it is unclear if ORT-based individualisation leads to an increase in live birth/ongoing pregnancy rates compared to a policy of giving all women 150 IU. The confidence interval is consistent with an increase of up to around six percentage points with ORT-based dosing (e.g. from 25% to 31%) or a very small decrease (< 1%). A difference of this magnitude could be important to many women. It is unclear if this is driven by improved outcomes in a particular subgroup. Further, ORT algorithms reduced the incidence of OHSS compared to standard dosing of 150 IU. However, the size of the effect is also unclear. The included studies were heterogeneous in design, which limited the interpretation of pooled estimates. It is likely that different ORT algorithms differ in their effectiveness. Current evidence does not provide a clear justification for adjusting the dose of 150 IU in poor or normal responders, especially as increased dose is associated with greater total FSH dose and cost. It is unclear whether a decreased dose in predicted high responders reduces OHSS, although this would appear to be the most likely explanation for the results.

Impact of 2.5 mg versus 5 mg letrozole co-treatment in an antagonist protocol for IVF: a retrospective study

Objective

The present study aimed to compare the effectiveness of two different doses of letrozole (2.5 mg and 5 mg daily) in an antagonist protocol for infertile women with normal ovarian reserve.

Methods

This retrospective cohort study included infertile women who underwent in vitro fertilization treatment with letrozole co-treatment at doses of 2.5 mg and 5 mg from 2007 - 2021 at Shanghai Ninth People's Hospital (Shanghai, China). The control group comprised infertile women who received gonadotropin-releasing hormone antagonist alone. The primary outcome was the cumulative live birth rate, while secondary outcomes included follicular phase endocrine parameters, ovarian stimulation outcomes, pregnancy outcomes, and the incidences of maternal and neonatal complications. Baseline and follow-up data were compared between the groups using ANOVA for normally distributed variables, the Kruskal-Wallis test for non-normally distributed variables, and the Chi-square test for categorical variables.

Results

A total of 422 participants were enrolled in the study, with 211 women in the antagonist group, 109 women in the 2.5 mg letrozole co-treatment group, and 102 women in the 5 mg letrozole co-treatment group. Letrozole co-treatment significantly suppressed oestradiol and follicle-stimulating hormone concentrations from stimulation day 5 and onwards, while increasing luteinizing hormone levels on stimulation day 5 and trigger day. The effect was more pronounced with a 5 mg dose of letrozole compared to a 2.5 mg dose (P < 0.05). Administration of 5 mg letrozole reduced the gonadotropin dose (P < 0.05) without negatively affecting the number of oocytes retrieved and subsequent embryo parameters (P > 0.05). The analysis of cumulative live birth rates showed rates of 29.4% in the letrozole 5 mg group, 27.5% in the letrozole 2.5 mg group, and 33.6% in the control group, with no statistically significant difference (P > 0.05). There were no reported pregnancy complications in the two letrozole groups. Additionally, there were no significant differences among the three groups in terms of gestational age and birth weight for both singleton and twin births.

Conclusion

This study indicates that the administration of letrozole in an antagonist protocol, at both 2.5 mg and 5 mg dosages, results in comparable clinical outcomes.

The importance of follicular flushing in optimizing oocyte retrieval

PURPOSE OF REVIEW

To critically evaluate the use of follicular flushing during oocyte retrieval.

RECENT FINDINGS

The latest meta-analysis evaluating follicular flushing does not favour its use over single aspiration. The randomized controlled trials (RCTs) included, however, are characterized by significant heterogeneity regarding the population analysed, the needle type and lumen used, the aspiration pressure applied and the number of flushing attempts performed. More importantly, information regarding the flow rate used for aspiration is scarce. The only RCT employing a constant flow rate between single aspiration and follicular flushing in women with monofollicular development, suggests that a higher number of oocytes is retrieved after follicular flushing.

SUMMARY

In order to eliminate clinical heterogeneity that might obscure the detection of the true effect of follicular flushing, randomization to single aspiration and follicular flushing should occur within the same patient. This can be achieved by randomly allocating each patient's ovary to either single aspiration or follicular flushing, maintaining similar flow rates between the groups compared.Given the importance of maximizing the number of oocytes retrieved from a given number of follicles developed, the conduction of properly designed RCTs evaluating follicular flushing is certainly required.

Effects of sequential cleavage and blastocyst embryo transfer on pregnancy outcomes in patients with poor ovarian response

The management of patients with poor ovarian response (POR) remains a major challenge for fertility specialists in in vitro fertilization-embryo transfer (IVF-ET). In this retrospective cohort study, we aimed to evaluate the clinical effect of sequential transfer on pregnancy outcomes in patients with POR. A total of 3579 POR patients who underwent the first frozen embryo transfer (FET) cycle were enrolled from January 2018 to April 2021. The patients were divided into three groups according to the embryo transfer (ET) strategy adopted: a study group that included POR patients in whom a cleavage-stage embryo (day 3) and a blastocyst (day 5/6) were transferred (sequential transfer group), and two control groups in whom two cleavage-stage embryos (D3-dET group) or two blastocysts (D5/6-dET group) were transferred. The study group was matched with the control groups at a ratio of 1:4 by propensity score matching (PSM). The main pregnancy outcomes measured were the live birth rate and multiple pregnancy rate. After PSM, the live birth rate in the sequential transfer group was significantly higher than that in the D3-dET group (44.2% vs. 34.3%, P = 0.019), and was similar to that in the D5/6-dET group (44.2% vs. 45.3%; P = 0.90). In addition, there was no increase in the risk of multiple pregnancy among POR patients undergoing sequential transfer compared with both D3-dET (26.7% vs. 25.6%, P = 0.85) and D5/6-dET (26.7% vs. 28.4%, P = 0.97) groups. These findings imply that sequential transfer is an effective option for POR patients and could be utilized after careful consideration.

Does the dose or type of gonadotropins affect the reproductive outcomes of poor responders undergoing modified natural cycle IVF (MNC-IVF)?

OBJECTIVE

Does the dose or type of gonadotropin affect the reproductive outcomes of poor responders undergoing IVF in a modified natural cycle (MNC-IVF)?

STUDY DESIGN

This is a retrospective cohort study including patients attending a tertiary referral University Hospital from 1st January 2017 until 1st March 2020. All predicted poor responders (Poseidon groups 3 and 4) who underwent MNC-IVF in our center were included. Mild ovarian stimulation (rFSH/uFSH/hp-hMG) was started when a follicle with a mean diameter of 12-14 mm was observed on ultrasound scan; GnRH antagonist was added from the next day onwards. Mature oocytes were inseminated using ICSI.

RESULTS

In total 484 patients undergoing 1398 cycles were included. Mean (SD) age and serum AMH were 38.2 (3.7) years and 0.28 (0.26) ng/ml, respectively. The daily dose of gonadotropins was either < 75 IU/d [11/1398 (0.8 %)] or 75 to < 100 IU/d [1303/1398 (93.2 %)] or ≥ 100 to 150 IU/d [84/1398 (6 %)]. Patients were stimulated with rFSH [251/1398 (18 %)], uFSH [45/1398 (3.2 %)] or hp-hMG [1102/1398 (78.8 %)]. Clinical pregnancy rate was 119/1398 (8.5 %). Live birth was achieved in 80/1398 (5.7 %) of cycles. There was no significant difference in rates of pregnancy and live birth across different types and doses of gonadotropins. The GEE multivariate regression analysis, adjusting for relevant confounders, showed that the type of treatment strategy (rFSH/uFSH/hp-hMG) and the daily dose of gonadotropins were not associated with live birth rates (LBR) (p value 0.08 and 0.8, respectively).

CONCLUSIONS

The type and daily dose of gonadotropins do not affect the reproductive outcome of poor responders undergoing MNC-IVF.

Impact of letrozole co-treatment during ovarian stimulation with gonadotrophins for IVF: a multicentre, randomized, double-blinded placebo-controlled trial

STUDY QUESTION

Does letrozole co-treatment during ovarian stimulation with gonadotrophins for IVF reduce the proportion of women with premature progesterone levels above 1.5 ng/ml at the time of triggering final oocyte maturation?

SUMMARY ANSWER

The proportion of women with premature progesterone above 1.5 ng/ml was not significantly affected by letrozole co-treatment.

WHAT IS KNOWN ALREADY

IVF creates multiple follicles with supraphysiological levels of sex steroids interrupting the endocrine milieu and affects the window of implantation. Letrozole is an effective aromatase inhibitor, normalizing serum oestradiol, thereby ameliorating some of the detrimental effects of IVF treatment.

STUDY DESIGN, SIZE, DURATION

A randomized, double-blinded placebo-controlled trial investigated letrozole intervention during stimulation for IVF with FSH. The trial was conducted at four fertility clinics at University Hospitals in Denmark from August 2016 to November 2018.

PARTICIPANTS/MATERIALS, SETTING, METHODS

A cohort of 129 women with expected normal ovarian reserve (anti-Müllerian hormone 8-32 nmol/l) completed an IVF cycle with fresh embryo transfer and received co-treatment with either 5 mg/day letrozole (n = 67) or placebo (n = 62), along with the FSH. Progesterone, oestradiol, FSH, LH and androgens were analysed in repeated serum samples collected from the start of the stimulation to the mid-luteal phase. In addition, the effect of letrozole on reproductive outcomes, total FSH consumption and adverse events were assessed.

MAIN RESULTS AND THE ROLE OF CHANCE

The proportion of women with premature progesterone >1.5 ng/ml was similar (6% vs 0% (OR 0.0, 95% CI [0.0; 1.6], P = 0.12) in the letrozole versus placebo groups, respectively), whereas the proportion of women with mid-luteal progesterone >30 ng/ml was significantly increased in the letrozole group: (59% vs 31% (OR 3.3, 95% CI [1.4; 7.1], P = 0.005)). Letrozole versus placebo decreased oestradiol levels on the ovulation trigger day by 68% (95% CI [60%; 75%], P < 0.0001). Other hormonal profiles, measured as AUC, showed the following results. The increase in LH in the letrozole group versus placebo group was 38% (95% CI [21%; 58%], P < 0.0001) and 34% (95% CI [11%; 61%], P = 0.006) in the follicular and luteal phases, respectively. In the letrozole group versus placebo group, testosterone increased by 79% (95% CI [55%; 105%], P < 0.0001) and 49% (95% CI [30%; 72%], P < 0.0001) in the follicular and luteal phases, respectively. In the letrozole group versus placebo group, the increase in androstenedione was by 85% (95% CI [59%; 114%], P < 0.0001) and 69% (95% CI [48%; 94%], P < 0.0001) in the follicular and luteal phases, respectively. The ongoing pregnancy rate was similar between the letrozole and placebo groups (31% vs 39% (risk-difference of 8%, 95% CI [-25%; 11%], P = 0.55)). No serious adverse reactions were recorded in either group. The total duration of exogenous FSH stimulation was 1 day shorter in the intervention group, significantly reducing total FSH consumption (mean difference -100 IU, 95% CI [-192; -21], P = 0.03).

LIMITATIONS, REASONS FOR CAUTION

Late follicular progesterone samples were collected on the day before and day of ovulation triggering for patient logistic considerations, and the recently emerged knowledge about diurnal variation of progesterone was not taken into account. The study was powered to detect hormonal variations but not differences in pregnancy outcomes.

WIDER IMPLICATIONS OF THE FINDINGS

Although the use of letrozole has no effect on the primary outcome, the number of women with a premature increase in progesterone on the day of ovulation triggering, the increased progesterone in the mid-luteal phase due to letrozole may contribute to optimizing the luteal phase endocrinology. The effect of letrozole on increasing androgens and reducing FSH consumption may be used in poor responders. However, the effect of letrozole on implantation and ongoing pregnancy rates should be evaluated in a meta-analysis or larger randomized controlled trial (RCT).

STUDY FUNDING/COMPETING INTEREST(S)

Funding was received from EU Interreg for ReproUnion and Ferring Pharmaceuticals, and Roche Diagnostics contributed with assays. N.S.M. and A.P. have received grants from Ferring, Merck Serono, Anecova and Gedeon Richter, and/or personal fees from IBSA, Vivoplex, ArtPred and SPD, outside the submitted work. The remaining authors have no competing interests.

TRIAL REGISTRATION NUMBERS

NCT02939898 and NCT02946684.

TRIAL REGISTRATION DATE

15 August 2016.

DATE OF FIRST PATIENT’S ENROLMENT

22 August 2016.

Type and dose of gonadotropins in poor ovarian responders: does it matter?

Infertile patients with a diminished ovarian reserve, also referred to as poor ovarian responders, constitute a substantial and increasing population of patients undergoing in vitro fertilization. The management of patients with poor ovarian response is still a controversial issue. Almost a century has passed since the introduction of the first gonadotropin. A broad collection of urinary and recombinant gonadotropins, including biosimilars, is commercially available now. Despite great advances in assisted reproductive technology, there remains uncertainty about the optimal treatment regimen for ovarian stimulation in poor ovarian responders. Although oocyte donation is the most successful and ultimate remedy for poor ovarian responders, most patients persist on using their own oocytes in several attempts, to achieve the desired pregnancy. The aim of this review is twofold: first, to provide an overview of the commercially available gonadotropins and summarize the available evidence supporting the use of one or another for ovarian stimulation in poor ovarian responders, and second, to address the controversies on the dosage of gonadotropins for this specific in vitro fertilization population.

SAY NO to mild ovarian stimulation for all poor responders: it is time to realize that not all poor responders are the same

Over the last 25 years, a vast body of literature has been published evaluating different treatment modalities for the management of poor ovarian responders. Despite the evidence that maximizing ovarian response can improve the chances of live born babies in poor responders, there are still voices suggesting that all poor responders are the same, irrespective of their age and their actual ovarian reserve. This has resulted in the suggestion of adopting a mild ovarian stimulation approach for all poor responders, based on the results of several trials which failed to identity differences when comparing mild and more intense stimulation in predicted poor responders. The current article analyzes in detail these studies and discusses the shortcomings in terms of type of population included, outcomes and settings performed, which may actually be responsible for the belief that only mild stimulation should be used. In the era of individualization in medicine, it must be realized that there are subgroups of predicted poor responders who will benefit from an individual rather than 'one fits all' mild stimulation approach and thus we should provide the same standard of treatment for all our poor responder patients.

Individualized ovarian stimulation in IVF/ICSI treatment: it is time to stop using high FSH doses in predicted low responders

In IVF/ICSI treatment, the FSH starting dose is often increased in predicted low responders from the belief that it improves the chance of having a baby by maximizing the number of retrieved oocytes. This intervention has been evaluated in several randomized controlled trials, and despite a slight increase in the number of oocytes—on average one to two more oocytes in the high versus standard dose group—no beneficial impact on the probability of a live birth has been demonstrated (risk difference, −0.02; 95% CI, −0.11 to 0.06). Still, many clinicians and researchers maintain a highly ingrained belief in ‘the more oocytes, the better’. This is mainly based on cross-sectional studies, where the positive correlation between the number of retrieved oocytes and the probability of a live birth is interpreted as a direct causal relation. If the latter would be present, indeed, maximizing the oocyte number would benefit our patients. The current paper argues that the use of high FSH doses may not actually improve the probability of a live birth for predicted low responders undergoing IVF/ICSI treatment and exemplifies the flaws of directly using cross-sectional data to guide FSH dosing in clinical practice. Also, difficulties in the de-implementation of the increased FSH dosing strategy are discussed, which include the prioritization of intermediate outcomes (such as cycle cancellations) and the potential biases in the interpretation of study findings (such as confirmation or rescue bias).

Minimal ovarian stimulation is an alternative to conventional protocols for older women according to Poseidon's stratification: a retrospective multicenter cohort study

OBJECTIVE

To investigate whether minimal ovarian stimulation (mOS) is as effective as conventional ovarian stimulation (cOS) for older women belonging to different groups according to the Poseidon criteria.

MATERIAL AND METHODS

Observational retrospective multicentre cohort including women from Poseidon's groups 2 and 4 that underwent in vitro fertilization (IVF). We performed a mixed-effects logistic regression model, adding as a random effect the patients and the stimulation cycle considering the dependence of data. Survival curves were employed as a measure of the cumulative live birth rate (CLBR). The primary outcomes were live birth rate per embryo transfer and CLBR per consecutive embryo transfer and oocyte consumed until a live birth was achieved.

RESULTS

A total of 2002 patients underwent 3056 embryo transfers (mOS = 497 and cOS = 2559). The live birth rates per embryo transfer in mOS and cOS showed no significant difference in both Poseidon's groups. Likewise, the logistic regression showed similar live birth rates between the two protocols in Poseidon's groups 2 (OR 1.165, 95% CI 0.77-1.77; p = 0.710) and 4 (OR 1.264 95% CI 0.59-2.70; p = 0.387). However, the survival curves showed higher CLBR per oocyte in women that received mOS (Poseidon group 2: p < 0.001 and Poseidon group 4: p = 0.039).

CONCLUSIONS

Minimal ovarian stimulation is a good alternative to COS as a first-line treatment for patients belonging to Poseidon's groups 2 and 4. The number of oocytes needed to achieve a live birth seems inferior in mOS strategy than cOS.

Effects of using letrozole in combination with the GnRH antagonist protocol for patients with poor ovarian response: A meta-analysis

This meta-analysis aimed to compare the outcomes of the gonadotrophin-releasing hormone (GnRH) antagonist/letrozole protocol with those of the conventional GnRH antagonist protocol for poor responders undergoing in vitro fertilization/intracytoplasmic sperm injection (IVF/ICSI). We searched for relevant articles in PubMed, EMBASE, Google Scholar, and retrieved 452 records. Eventually, we selected five eligible trials with data for 564 patients characterized as poor ovarian responders. Our meta-analysis revealed that the clinical pregnancy rate (per cycle) with administration of letrozole might be a higher than that in the control groups (risk rate [RR]: 1.57, 95% confidence interval [CI]: 1.00-2.44, p = 0.05). .Moreover,it indicated that the total dose of gonadotrophin was significantly decreased with the administration of letrozole compared to control groups(mean difference [MD]: -529.37, 95% CI: -1207.45 to -111.25, p = 0.001),.However, there was no statistical difference in the number of retrieved oocytes(MD: 0.59, 95% CI: -0.36-1.54, p = 0.22), cycle cancelation rate (RR: 0.81, 95% CI: 0.58-1.12, p = 0.20), or estradiol concentration on the day of HCG administration(MD: -28.19, 95% CI: -77.71-21.33, p = 0.26) in the presence or absence of letrozole combination in the GnRH antagonist protocol. In conclusion, letrozole administration might improve clinical pregnancy rate in conventional GnRH antagonist protocol for poor responders. Moreover, letrozole co-treatment aslo can reduce the economic burden of poor responders during the GnRH antagonist cycle. Nevertheless, large-scale and multi-center randomized controlled trials are needed to further evaluate the efficacy of adjunctive letrozole administration in the GnRH antagonist protocol.

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.

Fresh and cumulative live birth rates in mild versus conventional stimulation for IVF cycles in poor ovarian responders: a systematic review and meta-analysis

STUDY QUESTION

Are cumulative and live birth rates (LBRs) comparable in poor ovarian response women treated with different protocols of mild stimulation IVF (i.e. oral compounds, lower doses or shorter treatments) versus conventional IVF?

SUMMARY ANSWER

Mild ovarian stimulation (MOS) results in comparable outcomes to those of conventional stimulation in poor ovarian response patients with low ovarian reserve.

WHAT IS KNOWN ALREADY

Several randomized trials and meta-analyses have been published evaluating the role of mild (MOS) versus conventional ovarian stimulation in poor ovarian response patients. Most report a potentially higher safety profile, patient satisfaction and lower costs, suggesting that the higher cycle cancellation rate and fewer oocytes retrieved following MOS does not affect the final reproductive outcome. Additionally, over the last few years, new publications have added data regarding MOS, and shown the possible benefit of a higher oocyte yield which may also improve prognosis in patients with poor ovarian response.

STUDY DESIGN SIZE DURATION

We conducted a systematic search of relevant randomized controlled trials (RCTs). We searched electronic databases, including MEDLINE, EMBASE, LILACS-BIREME, CINAHL, The Cochrane Library, CENTRAL (Cochrane Register), Web of Science, Scopus, Trip Database and Open Grey, to identify all relevant studies published up to March 2020. We examined trial registries for ongoing trials. No publication-year or language restrictions were adopted. We explored the reference list of all included studies, reviews and abstracts of major scientific meetings. The primary outcomes were cumulative and fresh LBR (CLBR and FLBR) per woman randomized.

PARTICIPANTS/MATERIALS SETTING METHODS

We included subfertile women undergoing IVF/ICSI characterized as poor responders and compared primary and secondary outcomes between the different protocols of mild stimulation IVF (i.e. oral compounds, lower doses or shorter treatments) and conventional IVF. We used the PICO (Patients, Intervention, Comparison and Outcomes) model to select our study population.

MAIN RESULTS AND THE ROLE OF CHANCE

Overall, 15 RCTs were included in the meta-analysis. CLBR and FLBR were comparable between mild versus conventional stimulation (RR 1.15; 95% CI: 0.73 - 1.81; I2 = 0%, n = 424, moderate certainty and RR 1.01; 95% CI: 0.97 - 1.04; I 2 = 0%, n = 1001, low certainty, respectively). No difference was observed either when utilizing oral compounds (i.e. letrozole and clomiphene) or lower doses. Similarly, ongoing pregnancy rate (OPR) and clinical pregnancy rate (CPR) were equivalent when comparing the two groups (RR 1.01; 95% CI: 0.98 - 1.05; I 2 = 0%, n = 1480, low certainty, and RR 1.00; 95% CI: 0.97 - 1.03; I2 = 0%, n = 2355, low certainty, respectively). A significantly lower oocyte yield (mean differences (MD) -0.80; 95% CI: -1.28, -0.32; I2 = 83%, n = 2516, very low certainty) and higher rate of cycle cancellation (RR 1.48; 95% CI: 1.08 - 2.02; I2 = 62%, n = 2588, low certainty) was observed in the MOS group.

LIMITATIONS REASONS FOR CAUTION

The overall quality of the included studies was low to moderate. Even though strict inclusion criteria were used, the selected studies were heterogeneous in population characteristics and treatment protocols. We found no differences in CLBR between MOS and COS (95% CI: 0.73 - 1.81.).

WIDER IMPLICATIONS OF THE FINDINGS

MOS could be considered as a treatment option in low prognosis poor responder patients, given that it results in similar fresh and CLBRs compared with COS. A milder approach is associated with a lower number of oocytes retrieved and a higher cancellation rate, although treatment cost is significantly reduced. Future research should focus on which type of ovarian stimulation may be of benefit in better prognosis women.

STUDY FUNDING/COMPETING INTERESTS

There were no sources of financial support. N.P.P. received research grants, honoraria for lectures from: Merck Serono, MSD, Ferring Pharmaceuticals, Besins International, Roche Diagnostics, IBSA, Theramex and Gedeon Richter. P.D. received unrestricted grants and honoraria from Merck Serono, MSD and Ferring Pharmaceuticals. I.G.F. received unrestricted grants and honoraria from Merck Serono, MSD, Ferring Pharmaceuticals, Gedeon-Richter and IBSA. P.M.B. reported no conflict of interest.

TRIAL REGISTRATION NUMBER

CRD42020167260.

Comparison of in vitro fertilization cycles stimulated with 20 mg letrozole daily versus high-dose gonadotropins in Rotterdam Consensus ultra-poor responders: A proof of concept

OBJECTIVE

To evaluate if high-dose letrozole can be used successfully to stimulate poor responders for in vitro fertilization (IVF).

METHODS

This was a retrospective study conducted at a university hospital reproductive center. The analysis included women who were up to 42 years of age and were Rotterdam Consensus poor responders. A total of 247 patients received gonadotropins (300-450 IU daily) and 62 patients were stimulated with letrozole (20 mg daily) as part of an antagonist IVF protocol.

RESULTS

The use of 20 mg of letrozole decreased the total dose of gonadotropins used (645 ± 175 IU vs. 5360 ± 1028 IU, P = 0.001) and resulted in lower costs of stimulation medications ($ 555.56 ± $ 150 vs. $ 4616 ± $ 885 Canadian Dollars; P = 0.001). Pregnancy per cycle (14.5%) and per transfer (16%) rates were legitimate for this low prognosis group and may have been better than or similar to those with high-dose gonadotropins. The rate of cycle cancellation may have been reduced in the letrozole versus gonadotropin group (11% vs. 38%; P = 0.001).

CONCLUSION

Letrozole (20 mg daily) may be used to reduce the cost of ovarian stimulation in ultra-poor responders, significantly reducing the cost of the IVF cycle with probably at least similar outcomes to high-dose gonadotropins.

Co-Administration of Clomiphene Citrate and Letrozole in Mild Ovarian Stimulation Versus Conventional Controlled Ovarian Stimulation Among POSEIDON Group 4 Patients

This retrospective study assessed the effect of the co-administration of clomiphene citrate (CC) and letrozole in mild ovarian stimulation, compared to conventional regimens, among Patient-Oriented Strategies Encompassing Individualized Oocyte Number (POSEIDON) Group 4 patients. There were 114 POSEIDON Group 4 patients undergoing in vitro fertilization treatments with 216 stimulation cycles recruited from a Taiwan's reproductive center during 2016-2020. Main outcomes were the numbers, quality of retrieved oocytes and embryo development. Pregnancy outcomes were assessed after embryo transfers. Per stimulation cycle, patients receiving mild stimulation with a combination of CC and letrozole (study group) versus those with COS (control group) had lower numbers of pre-ovulatory follicles (2.00 ± 1.23 vs. 2.37 ± 1.23, p=0.0066) and oocytes retrieved (1.83 ± 1.17 vs. 2.37 ± 1.23, p=0.0017), and lower follicular output rate (58.6% vs. 68.38%, p=0.0093) and mature oocyte output rate (44.29% vs. 52.88%, p=0.0386) but a higher top-quality metaphase II oocyte ratio (66.7% vs. 54.59%, p=0.0444) and a similar fertilization rate (91.67% vs. 89.04%, p=0.4660). With adjustment for significant between-group baseline differences using multivariable logistic generalized estimating equation model analyses, there was no statistical difference in oocytes retrieved and embryo development between the study and control groups, and insignificant increases in successful pregnancies in the study group were found compared to the control group (i.e., odds ratios [95% CIs]: 1.13 [0.55, 232] and 1.50 [0.65, 3.49] for ongoing pregnancy and live birth, respectively). For POSEIDON Group 4 patients, cotreatment of CC and letrozole in mild stimulation may increase the high-quality oocyte ratio and yield comparable fertilization rate and pregnancy outcomes.

Comparative Effectiveness of Mild or Conventional GnRH-Antagonist Protocols for Ovarian Stimulation in Poor Responders (Poseidon Group 4)

Background and Aims: A panel of experts (the Poseidon Group) introduced a new and more detailed stratification for poor ovarian responders in order to predict the prognosis of IVF outcome according to the sensitivity to FSH. However, various arguments about the management strategy of these patients still remain, including the convenience and the cost. Therefore, this study was conducted to compare the efficacy of mild and conventional GnRH antagonist ovarian stimulation prescribed in patients classified in Poseidon Group 4.

Methods: This retrospective cohort study included 359 poor responder patients (Poseidon Group 4) treated with mild or conventional GnRH antagonist stimulation regimens from 8/2017 to 7/2019 at Tam Anh Hospital ART Center. The main outcomes were the index of Follicular Output Rate (FORT) or Follicle to Oocyte Index (FOI), the number of day-2 embryos and top-quality embryos obtained. The t-test and Mann–Whitney U test in SPSS v25.0 was used to analyze the continuous data and Chi-squared/Exact test was used for binary variables. Multiple linear regression analysis was done by using Stata versions 15.0 to measure association between primary endpoints with stimulation regimen controlled for covariates and possible confounding factors.

Results: In the overall group of poor responders, the conventional GnRH antagonist protocol performed better than the mild protocol. Subsequently, data were analyzed according to the AFC. In women with AFC &lt; 3, no significant differences were observed between the 2 regimens regarding FORT (p = 0.71), FOI (p = 0.12), the number of day-2-embryos (p = 0.052) and the number of top-quality embryos (p = 0.26). In contrast, in women with AFC ≥ 3, mild stimulation regimen resulted in significantly poorer outcome compared to the conventional GnRH antagonist regimen, regarding FORT (p &lt; 0.01), FOI (p &lt; 0.01), the number of day-2-embryos (p &lt; 0.01) and top-quality embryos (p = 0.01).

Conclusions: Considering poor responders classified in Poseidon Group 4, both ovarian stimulation regimens resulted in similar outcome for patients with a very low ovarian reserve (AFC &lt; 3). In contrast, the GnRH conventional antagonist protocol with maximum initial FSH dose (300–375 IU/day) and supplementary LH (75–150 IU/day) was more effective than the mild one for patients whose ovarian reserve was less reduced. The Clinical Trial was approved by the Ethnical Biomedical Research Committee Tam Anh General Hospital.

Adjuvant treatment strategies in ovarian stimulation for poor responders undergoing IVF: a systematic review and network meta-analysis

BACKGROUND

Despite great advances in assisted reproductive technology, poor ovarian response (POR) is still considered as one of the most challenging tasks in reproductive medicine.

OBJECTIVE AND RATIONALE

The aim of this systemic review is to evaluate the role of different adjuvant treatment strategies on the probability of pregnancy achievement in poor responders undergoing IVF. Randomized controlled trials (RCTs) comparing 10 adjuvant treatments [testosterone, dehydroepiandrosterone (DHEA), letrozole, recombinant LH, recombinant hCG, oestradiol, clomiphene citrate, progesterone, growth hormone (GH) and coenzyme Q10 (CoQ10)] were included.

SEARCH METHODS

Relevant studies published in the English language were comprehensively selected using PubMed, Embase and the Cochrane Central Register of Controlled Trials (CENTRAL) until 11 July 2018. We included studies that investigated various adjuvant agents, including androgen and androgen-modulating agents, oestrogen, progesterone, clomiphene citrate, GH and CoQ10, during IVF treatment and reported subsequent pregnancy outcomes. The administration of GnRH analogs and gonadotrophins without adjuvant treatment was set as the control. We measured study quality based on the methodology and categories listed in the Cochrane Collaboration Handbook. This review protocol was registered with PROSPERO (CRD42018086217).

OUTCOMES

Of the 1124 studies initially identified, 46 trials reporting on 6312 women were included in this systematic review, while 19 trials defining POR using the Bologna criteria reporting 2677 women were included in the network meta-analysis. Compared with controls, DHEA and CoQ10 treatments resulted in a significantly higher chance of clinical pregnancy [odds ratio (OR) 2.46, 95% CI 1.16 to 5.23; 2.22, 1.08-4.58, respectively]. With regard to the number of retrieved oocytes, HCG, oestradiol and GH treatments had the highest number of oocytes retrieved [weighted mean difference (WMD) 2.08, 0.72 to 3.44; 2.02, 0.23 to 3.81; 1.72, 0.98 to 2.46, compared with controls, respectively]. With regard to the number of embryos transferred, testosterone and GH treatment led to the highest number of embryos transferred (WMD 0.72, 0.11 to 1.33; 0.67, 0.43 to 0.92; compared with controls, respectively). Moreover, GH resulted in the highest oestradiol level on the HCG day (WMD 797.63, 466.45 to 1128.81, compared with controls). Clomiphene citrate, letrozole and GH groups used the lowest dosages of gonadotrophins for ovarian stimulation (WMD 1760.00, -2890.55 to -629.45; -1110.17, -1753.37 to -466.96; -875.91, -1433.29 to -282.52; compared with controls, respectively). CoQ10 led to the lowest global cancelation rate (OR 0.33, 0.15 to 0.74, compared with controls).

WIDER IMPLICATIONS

For patients with POR, controlled ovarian stimulation protocols using adjuvant treatment with DHEA, CoQ10 and GH showed better clinical outcomes in terms of achieving pregnancy, and a lower dosage of gonadotrophin required for ovulation induction. Furthermore, high-level RCT studies using uniform standards for POR need to be incorporated into future meta-analyses.

The Conundrum of Poor Ovarian Response: From Diagnosis to Treatment

Despite recent striking advances in assisted reproductive technology (ART), poor ovarian response (POR) diagnosis and treatment is still considered challenging. Poor responders constitute a heterogeneous cohort with the common denominator of under-responding to controlled ovarian stimulation. Inevitably, respective success rates are significantly compromised. As POR pathophysiology entails the elusive factor of compromised ovarian function, both diagnosis and management fuel an ongoing heated debate depicted in the literature. From the criteria employed for diagnosis to the plethora of strategies and adjuvant therapies proposed, the conundrum of POR still puzzles the practitioner. What is more, novel treatment approaches from stem cell therapy and platelet-rich plasma intra-ovarian infusion to mitochondrial replacement therapy have emerged, albeit not claiming clinical routine status yet. The complex and time sensitive nature of this subgroup of infertile patients indicates the demand for a consensus on a horizontally accepted definition, diagnosis and subsequent effective treating strategy. This critical review analyzes the standing criteria employed in order to diagnose and aptly categorize POR patients, while it proceeds to critically evaluate current and novel strategies regarding their management. Discrepancies in diagnosis and respective implications are discussed, while the existing diversity in management options highlights the need for individualized management.

Does daily co administration of gonadotropins and letrozole during the ovarian stimulation improve IVF outcome for poor and sub optimal responders?

Background

Co-administration of letrozole during the first 5 days of ovarian stimulation was suggested to improve IVF outcomes in poor responders. We aimed to determine whether poor/sub-optimal responders might benefit from Letrozole co-treatment throughout the entire stimulation course.

Methods

We retrospectively reviewed the medical files of women who demonstrated poor (oocyte yield ≤3) and sub-optimal (4 ≤ oocyte yield ≤9) ovarian response during conventional multiple-dose antagonist stimulation protocols and were co-treated in a subsequent cycle with 5 mg Letrozole from the first day of stimulation until trigger day. A self-paired comparison between gonadotropins-only and gonadotropins-letrozole cycles was performed.

Results

Twenty-four patients were included. Mean patients’ age was 39.83 ± 4.60 and mean day-3-FSH was 12.77 ± 4.49 IU/m. Duration of stimulation and total gonadotropins dose were comparable between the two cycle groups. Peak estradiol levels were significantly lower in gonadotropins-letrozole cycles (2786.74 ± 2118.53 vs 1200.13 ± 535.98, p < 0.05). Number of retrieved oocytes (3.29 ± 2.15 vs 6.46 ± 3.20, p < 0.05), MII-oocytes (2.47 ± 1.65 vs 5.59 ± 3.20, p < 0.05), 2PN-embryos (1.78 ± 1.50, 4.04 ± 2.74, p < 0.05) and top-quality embryos (0.91 ± 0.97 vs. 2.35 ± 1.66, p < 0.05) were significantly higher in the gonadotropins-letrozole cycles. Clinical pregnancy rate in gonadotropins-letrozole cycles was 31.5%.

Conclusion

Letrozole co-treatment during the entire stimulation course improves ovarian response and IVF outcomes in poor/sub-optimal responders.

Effect of adding letrozole to gonadotropin on in vitro fertilization outcomes: An RCT

Background

Aromatase inhibitors prevent the aromatization of androgens into estrogens, which reduces the negative feedback of estrogen on the hypothalamic-pituitary axis. It is clear that increasing the secretion of follicle-stimulating hormones results in an increased follicular growth.

Objective

This study aimed to evaluate the effect of adding letrozole to gonadotropin on in vitro fertilization outcomes in normal responders.

Materials and Methods

In this randomized clinical trial, 100 normal responder women candidate for controlled ovarian stimulation were randomly enrolled in two groups (n = 50/each). In the case group letrozole was added to gonadotropin in the antagonist protocol. The control group received the conventional antagonist protocol. The main outcome was clinical and chemical pregnancy; and the second outcomes were the number of mature oocytes, the fertilization rate, estradiol level, and the total dose of gonadotropins.

Results

Basic clinical and demographic features were comparable between the groups. Estradiol level on the day of human-chorionic-gonadotropin administration and the total gonadotropin consumption were significantly higher in the control group than the case group (p = 0.045). In addition, the number of MII oocytes was higher (but not significantl) in the case group than the control group (p = 0.09). Moreover, the endometrial thickness was significantly lower in the case group. There were no significant differences in fertilization rate and chemical and clinical pregnancy rates between the two groups.

Conclusion

Although adding letrozole to gonadotropin in normal responders reduces the total dose of gonadotropin, it does not improve the pregnancy outcomes.

Mild stimulation protocol vs conventional controlled ovarian stimulation protocol in poor ovarian response patients: a prospective randomized controlled trial

PURPOSE

To compare the efficacy of mild ovarian stimulation protocol and conventional controlled ovarian stimulation (COS) protocol for poor ovarian response (POR) patients undergoing in vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI).

METHODS

This single-center prospective randomized controlled trial conducted from September 2013 to September 2015, including 191 patients who met the Bologna criteria of POR. Ninety-seven patients allocated to the mild ovarian stimulation group (MS group) were stimulated according to the letrozole/antagonist protocol, while 94 patients in the controlled ovarian stimulation group (COS group) were stimulated according to a high dose of gonadotropin (Gn) combined with gonadotropin-releasing hormone agonist (GnRH-a) stop protocol. The cumulative live birth rate was the primary outcome. Chinese clinical trial number ChiCTR-TRC-13003454.

RESULTS

Comparing with the COS group, both the stimulation duration and the total gonadotropin dose were significantly shorter and lower in the MS group (P < 0.001). A higher number of retrieved oocytes (P = 0.003) and transferrable embryos (P = 0.029) were obtained in the COS group. The cumulative live birth rates (OR 1.103; 95% CI 0.53 to 2.28; P = 0.791) were comparable between the two groups.

CONCLUSIONS

The increase of Gn dose during ovulation stimulation was associated with a higher number of transferrable embryos for POR patients, but this increase did not lead to a concomitant improvement of reproductive outcome, especially in terms of the cumulative live birth rate. Using a mild stimulation protocol was economically preferential while it was as effective as higher doses of Gn stimulation protocol in reproductive outcome for POR patients.

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

Mild ovarian stimulation is a treatment option for poor responders in IVF treatment. Our updated review evaluated mild IVF solely from randomized controlled trials (RCTs) that used genuine low-dose gonadotrophin (≤150 IU daily) alone or in combination with oral medications, comparing it with conventional-dose (>150 IU/ daily) IVF for poor responders. Electronic searches on MEDLINE, Embase, The Cochrane Central Register of Controlled Trials and PreMEDLINE, and hand searches from 2002 up to 31 January 2019, identified 14 RCTs, which were compiled with the above inclusion criteria. The risk of bias (ROB) and quality of evidence (QOE) were assessed as per Cochrane Collaboration. Meta-analyses found no difference in live birth rate (four RCTs, n = 1057, RR 0.91, CI 0.66 to 1.25) (moderate QOE), ongoing pregnancy rate (six RCTs, n = 1782, RR 1.01, CI 0.86 to 1.20) (moderate-high QOE) and cycle cancellation rates (14 RCTs, n = 2746, RR 1.38, CI 0.99 to 1.92) (low QOE). Fewer oocytes and embryos were obtained from mild IVF; however, the number and proportion of high-grade embryos were similar. Mild IVF resulted in reduced gonadotrophin use and cost. The inference remained unchanged when smaller studies with ROB were excluded, or whether gonadotrophin alone or combination with oral medication was used. The evidence of equal efficacy from a pooled population, which was adequately powered for live birth, supported a mild IVF strategy for poor responders in preference to more expensive conventional IVF. Although clinical heterogeneity remained a limiting factor, it increased the generalizability of the findings.

Cumulative Live Birth Rate and Cost-Effectiveness Analysis of Gonadotropin Releasing Hormone-Antagonist Protocol and Multiple Minimal Ovarian Stimulation in Poor Responders

BACKGROUND

The overall cumulative live birth rate (CLBR) of poor ovarian responders (POR) is extremely low. Minimal ovarian stimulation (MOS) provides a relatively realistic solution for ovarian stimulation in POR. Our study aimed to investigate whether multiple MOS strategies resulted in higher CLBR compared to conventional gonadotropin releasing hormone (GnRH) antagonists in POR.

METHODS

This retrospective study included 699 patients (1,058 cycles) from one center, who fulfilled the Bologna criteria between 2010 and 2018. Overall, 325 women (325 cycles) were treated with one-time conventional GnRH antagonist ovarian stimulation (GnRH-antagonist). Another 374 patients (733 cycles) were treated with multiple MOS including natural cycles. CLBR and time-and-cost-benefit analyses were compared between these two groups of women.

RESULTS

GnRH antagonists provided more retrieved oocytes, meiosis II oocytes, fertilized oocytes, and more viable embryos compared to both the first MOS (p < 0.001) and the cumulative corresponding numbers in multiple MOSs (p < 0.001). For the first in vitro fertilization (IVF) cycle, GnRH antagonists resulted in higher CLBR than MOS [12.92 versus 4.54%, adjusted OR (odds ratio) 2.606; 95% CI (confidence interval) 1.386, 4.899, p = 0.003]. The one-time GnRH-antagonist induced comparable CLBR (12.92 versus 7.92%, adjusted OR 1.702; 95% CI 0.971, 2.982, p = 0.063), but a shorter time to live birth [9 (8, 10.75) months versus 11 (9, 14) months, p = 0.014] and similar financial expenditure compared to repeated MOS [20,838 (17,953, 23,422) ¥ versus 21,261.5 (15,892.5, 35,140.25) ¥, p = 0.13].

CONCLUSION

Both minimal ovarian stimulation (MOS) and GnRH-antagonists provide low chances of live birth in poor responders. The GnRH antagonist protocol is considered a suitable choice for PORs with comparable CLBR, shorter times to live birth, and similar financial expenditure compared to repeated MOS.

The stimulation protocol in poor responder IVF; a minimal or high-dose stimulation? - A meta-analysis

Background To determine whether a minimal stimulation (MS) or high-dose stimulation (HDS) protocol is a better option for patients classified as poor ovarian responders (POR) in terms of reproductive and pregnancy outcomes. Materials and methods A database search for evaluation of the study outcome by using meta-analysis method was carried out. The primary outcome was the clinical pregnancy (CP) rate for each of two groups, namely, the MS and HDS groups. The secondary outcomes were the gonadotropin dose used, duration of stimulation, cancellation rate, number of oocytes retrieved, number of fertilized oocytes, number of embryos transferred and live birth rates. Results Across five databases, 4670 potential studies for further screening were selected. But ultimately only six studies, three RCTs and three retrospective or case control studies were selected that meet the Bologna criteria for POR. In all there were 624 cycles. Our meta-analysis indicated that the CP rates, cycle cancellation rates, durations of stimulation, numbers of oocytes fertilized and numbers of embryos transferred were not statistically significant. Clearly, the number of oocytes retrieved in the MS group was significantly lower than in the HDS group, while the HDS group consumed significantly higher doses of gonadotropins than the MS group. The live birth rates were significantly higher in the MS group than in the HDS group. Conclusion MS should be the first-line protocol for managing POR because the live birth rate is significantly higher, even with fewer oocytes retrieved.

Letrozole as co-treatment agent in ovarian stimulation antagonist protocol in poor responders: A double-blind randomized clinical trial

Background

Ovarian stimulation (OS) for poor ovarian response (POR) patients is still a major challenge in assisted reproductive techniques. Aromatase inhibitors as co-treatment in antagonist protocol are suggested to these patients, but there are controversial reports.

Objective

To evaluate the effectiveness Letrozole (LZ) as adjuvant treatment in gonadotropin-releasing hormone (GnRH)-antagonist protocol in POR patients undergoing in vitro fertilization/ intracytoplasmic sperm injection cycles.

Materials and Methods

This double-blind randomized clinical trial was conducted in Arash women's hospital. One hundred sixty infertile women with POR based on Bologna criteria were allocated into two groups randomly: LZ + GnRH-antagonist (LA) and placebo + GnRH-antagonist (PA) groups. In the experimental group, the patients received 5 mg LZ on the first five days of OS with 150 IU of recombinant human follicle-stimulating hormone (rFSH) and 150 IUof human menopausal gonadotropin (HMG). The cycle outcomes were compared between groups.

Results

The total number of retrieved oocytes and the metaphase II oocytes in LA-treated group were significantly higher than those in the control group (p = 0.008, p = 0.002). The dosage of hMG used and the duration of OS and antagonist administration in LZ-treated group were significantly lower than those of the control group. The number of patients with no oocyte, in the control group, was higher than the LZ-treated group, and the clinical pregnancy rate in LA-treated group (25%) was higher than the control group (18%); however, the differences were not significant statistically.

Conclusion

Adding 5 mg of LZ to rFSH/hMG antagonist protocol may improve the in vitro fertilization/intracytoplasmic sperm injectioncycle outcome in POR patients.

Ovarian stimulation modalities in poor responders

In a group of IVF/ICSI cycles, despite the appropriate ovarian stimulation, the number of oocytes collected is below the expected value. This condition is defined as poor ovarian response (POR) to stimulation. POR brings the risk of cycle cancellation with an estimated rate of 20%. Infertility experts are trying to improve cycle outcomes of POR cases with multiple modifications. This review article will present the latest modifications on the management of POR. The studies performed for improving cycle outcome in POR cases were evaluated and their notable results were presented. The first intervention among infertility specialists is to make a standard definition for POR. The BOLOGNA criteria and the subsequent POSEIDON group definitions are the latest updates in POR management. GnRH antagonists, estradiol priming, double stimulation, letrozole administration, DHEA, and herbal therapy supplementations are the recent modifications done to improve oocyte retrieval and subsequent embryo transfer for POR cases. This review article presents the encouraging methods applied for POR cases to improve cycle outcome.

Double mild stimulation and egg collection in the same cycle for management of poor ovarian responders

PURPOSE

To evaluate the effect of double stimulations during the follicular and luteal phases in women with poor ovarian response (POR) in in-vitro fertilization/intracytoplasmic sperm injection (IVF/ICSI) cycles.

BASIC PROCEDURES

This prospective clinical study was performed in Royan Institute from October 2014 to January 2016. 121 patients were diagnosed as POR on the basis of Bologna criteria were included. Double stimulations were performed during the follicular and luteal phases by Letrozole, Clomid, hMG and GnRH-agonist. The patients' present cycle outcomes were compared with those of the previous cycle results using appropriate statistical tests.

MAIN FINDING

The total of 104 (85.9%) patients completed the stimulation stages. The analysis revealed the number of retrieved oocytes after the first and second stimulations did not differ (P = 0.2); however, the fertilization rate and the number of frozen embryos after the first stimulation were significantly higher than those of in the second stimulation (P < 0.001 and P = 0.03), indicating the better quality of retrieved oocytes after the first stimulation. The mean number of MII oocytes and the fertilization rate after Shanghai protocol were higher than those of the previous antagonist protocol with a substantial trend toward significance (P = 0.06), which can be clinically important. The cancellation rate (33%) due to no ovarian response and no embryo formation was still high in these patients.

PRINCIPAL CONCLUSION

Since the intensity of stimulation in both stages was mild, this protocol can be considered a time-efficient and patient friendly regime; however, more studies are required with emphasis on its cost-effectiveness.

Conventional versus minimal ovarian stimulation: an intra-patient comparison of ovarian response in poor-responder women according to Bologna Criteria

RESEARCH QUESTION

Is minimal ovarian stimulation (MOS) as effective as conventional ovarian stimulation (COS) in ovarian response and embryo quality in the same 46 poor-responder patients according to the Bologna criteria?

DESIGN

An intra-patient comparison of patients undergoing both protocols. Ovaries were stimulated with either a gonadotrophin-releasing hormone antagonist protocol and a combination of recombinant FSH and highly purified human menotrophin (HP-HMG) daily (COS), or with the use of clomiphene citrate 50 mg daily and 150 IU of HP-HMG or recombinant FSH every other day from simulation day 4 (MOS).

RESULTS

After MOS, significantly more good-quality embryos (1.0 ± 1.2 versus 0.3 ± 0.6) (P = 0.002), oocytes (3.2 ± 1.9 versus 2.0 ± 1.8) (P = 0.002), and mature (metaphase II) oocytes (2.6 ± 1.7 versus 1.6 ± 1.7) (P = 0.001) were obtained. In COS cycles, a significantly higher total gonadotrophin dose was needed per good-quality embryo (+2194 IU; 95% CI 618 to 3170).

CONCLUSIONS

In poor responder patients, MOS is a good alternative when COS has failed, or even as a first-line treatment. It offered a significantly greater number of good-quality embryos as well as a higher number of oocytes, using significantly lower doses of gonadotrophins per oocyte and embryo obtained.

Comparison of pregnancy rates for poor responders using IVF with mild ovarian stimulation versus conventional IVF: a guideline

Mild-stimulation protocols with in vitro fertilization (IVF) generally aim to use less medication than conventional IVF. This guideline evaluates pregnancy and live-birth rates in patients expected to be poor responders using mild ovarian stimulation and natural-cycle protocols vs conventional IVF.

Individualised gonadotropin dose selection using markers of ovarian reserve for women undergoing in vitro fertilisation plus intracytoplasmic sperm injection (IVF/ICSI)

BACKGROUND

During a cycle of in vitro fertilisation plus intracytoplasmic sperm injection (IVF/ICSI), women receive daily doses of gonadotropin follicle-stimulating hormone (FSH) to induce multifollicular development in the ovaries. Generally, the dose of FSH is associated with the number of eggs retrieved. A normal response to stimulation is often considered desirable, for example the retrieval of 5 to 15 oocytes. Both poor and hyper-response are associated with increased chance of cycle cancellation. Hyper-response is also associated with increased risk of ovarian hyperstimulation syndrome (OHSS). Clinicians often individualise the FSH dose using patient characteristics predictive of ovarian response such as age. More recently, clinicians have begun using ovarian reserve tests (ORTs) to predict ovarian response based on the measurement of various biomarkers, including basal FSH (bFSH), antral follicle count (AFC), and anti-Müllerian hormone (AMH). It is unclear whether individualising FSH dose based on these markers improves clinical outcomes.

OBJECTIVES

To assess the effects of individualised gonadotropin dose selection using markers of ovarian reserve in women undergoing IVF/ICSI.

SEARCH METHODS

We searched the Cochrane Gynaecology and Fertility Group Specialised Register, Cochrane Central Register of Studies Online, MEDLINE, Embase, CINAHL, LILACS, DARE, ISI Web of Knowledge, ClinicalTrials.gov, and the World Health Organisation International Trials Registry Platform search portal from inception to 27th July 2017. We checked the reference lists of relevant reviews and included studies.

SELECTION CRITERIA

We included trials that compared different doses of FSH in women with a defined ORT profile (i.e. predicted low, normal or high responders based on AMH, AFC, and/or bFSH) and trials that compared an individualised dosing strategy (based on at least one ORT measure) versus uniform dosing or a different individualised dosing algorithm.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures recommended by Cochrane. Primary outcomes were live birth/ongoing pregnancy and severe OHSS. Secondary outcomes included clinical pregnancy, moderate or severe OHSS, multiple pregnancy, oocyte yield, cycle cancellations, and total dose and duration of FSH administration.

MAIN RESULTS

We included 20 trials (N = 6088); however, we treated those trials with multiple comparisons as separate trials for the purpose of this review. Meta-analysis was limited due to clinical heterogeneity. Evidence quality ranged from very low to moderate. The main limitations were imprecision and risk of bias associated with lack of blinding.Direct dose comparisons in women according to predicted responseAll evidence was low or very low quality.Due to differences in dose comparisons, caution is warranted in interpreting the findings of five small trials assessing predicted low responders. The effect estimates were very imprecise, and increased FSH dosing may or may not have an impact on rates of live birth/ongoing pregnancy, OHSS, and clinical pregnancy.Similarly, in predicted normal responders (nine studies, three comparisons), higher doses may or may not impact the probability of live birth/ongoing pregnancy (e.g. 200 versus 100 international units: OR 0.88, 95% CI 0.57 to 1.36; N = 522; 2 studies; I2 = 0%) or clinical pregnancy. Results were imprecise, and a small benefit or harm remains possible. There were too few events for the outcome of OHSS to enable any inferences.In predicted high responders, lower doses may or may not have an impact on rates of live birth/ongoing pregnancy (OR 0.98, 95% CI 0.66 to 1.46; N = 521; 1 study), OHSS, and clinical pregnancy. However, lower doses probably reduce the likelihood of moderate or severe OHSS (Peto OR 2.31, 95% CI 0.80 to 6.67; N = 521; 1 study).ORT-algorithm studiesFour trials compared an ORT-based algorithm to a non-ORT control group. Rates of live birth/ongoing pregnancy and clinical pregnancy did not appear to differ by more than a few percentage points (respectively: OR 1.04, 95% CI 0.88 to 1.23; N = 2823, 4 studies; I2 = 34%; OR 0.96, 95% CI 0.82 to 1.13, 4 studies, I2=0%, moderate-quality evidence). However, ORT algorithms probably reduce the likelihood of moderate or severe OHSS (Peto OR 0.58, 95% CI 0.34 to 1.00; N = 2823; 4 studies; I2 = 0%, low quality evidence). There was insufficient evidence to determine whether the groups differed in rates of severe OHSS (Peto OR 0.54, 95% CI 0.14 to 1.99; N = 1494; 3 studies; I2 = 0%, low quality evidence). Our findings suggest that if the chance of live birth with a standard dose is 26%, the chance with ORT-based dosing would be between 24% and 30%. If the chance of moderate or severe OHSS with a standard dose is 2.5%, the chance with ORT-based dosing would be between 0.8% and 2.5%. These results should be treated cautiously due to heterogeneity in the study designs.

AUTHORS' CONCLUSIONS

We did not find that tailoring the FSH dose in any particular ORT population (low, normal, high ORT), influenced rates of live birth/ongoing pregnancy but we could not rule out differences, due to sample size limitations. In predicted high responders, lower doses of FSH seemed to reduce the overall incidence of moderate and severe OHSS. Moderate-quality evidence suggests that ORT-based individualisation produces similar live birth/ongoing pregnancy rates to a policy of giving all women 150 IU. However, in all cases the confidence intervals are consistent with an increase or decrease in the rate of around five percentage points with ORT-based dosing (e.g. from 25% to 20% or 30%). Although small, a difference of this magnitude could be important to many women. Further, ORT algorithms reduced the incidence of OHSS compared to standard dosing of 150 IU, probably by facilitating dose reductions in women with a predicted high response. However, the size of the effect is unclear. The included studies were heterogeneous in design, which limited the interpretation of pooled estimates, and many of the included studies had a serious risk of bias.Current evidence does not provide a clear justification for adjusting the standard dose of 150 IU in the case of poor or normal responders, especially as increased dose is generally associated with greater total FSH dose and therefore greater cost. However, a decreased dose in predicted high responders may reduce OHSS.

Low dosing of gonadotropins in in vitro fertilization cycles for women with poor ovarian reserve: systematic review and meta-analysis

OBJECTIVE

To evaluate the effectiveness of low doses of gonadotropins and gonadotropins combined with oral compounds compared with high doses of gonadotropins in ovarian stimulation regimens in terms of ongoing pregnancy per fresh IVF attempt in women with poor ovarian reserve undergoing IVF/intracytoplasmic sperm injection (ICSI) treatment.

DESIGN

A systematic review and meta-analysis of randomized controlled studies that evaluate the effectiveness of low dosing of gonadotropins alone or combined with oral compounds compared with high doses of gonadotropins in women with poor ovarian reserve undergoing IVF/ICSI treatment.

SETTING

Not applicable.

PATIENT(S)

Subfertile women with poor ovarian reserve undergoing IVF/ICSI treatment.

INTERVENTION(S)

We searched the PubMed, EMBASE, Web of Science, the Cochrane Library, and the Clinical Trials Registry using medical subject headings and free text terms up to June 2016, without language or year restrictions. We included randomized controlled studies (RCTs) enrolling subfertile women with poor ovarian reserve undergoing IVF/ICSI treatment and comparing low doses of gonadotropins and gonadotropins combined with oral compounds versus high doses of gonadotropins. We assessed the risk of bias using the criteria recommended by the Cochrane Collaboration. We pooled the results by meta-analysis using the fixed and random effects model.

MAIN OUTCOMES MEASURE(S)

The primary outcome was ongoing pregnancy rate (PR) per woman randomized.

RESULT(S)

We retrieved 787 records. Fourteen RCTs (N = 2,104 women) were included in the analysis. Five studies (N = 717 women) compared low doses of gonadotropins versus high doses of gonadotropins. There was no evidence of a difference in ongoing PR (2 RCTs: risk rate 0.98, 95% confidence interval 0.62-1.57, I² = 0). Nine studies (N = 1,387 women) compared ovarian stimulation using gonadotropins combined with the oral compounds letrozole (n = 6) or clomiphene citrate (CC) (n = 3) versus high doses of gonadotropins. There was no evidence of a difference in ongoing PR (3 RCTs: risk rate 0.90, 95% confidence interval 0.63-1.27, I² = 0).

CONCLUSION(S)

We found no evidence of a difference in pregnancy outcomes between low doses of gonadotropins and gonadotropins combined with oral compounds compared with high doses of gonadotropins in ovarian stimulation regimens. Whether low doses of gonadotropins or gonadotropins combined with oral compounds is to be preferred is unknown, as they have never been compared head to head. A health economic analysis to test the hypothesis that an ovarian stimulation with low dosing is more cost-effective than high doses of gonadotropins is needed.

PROSPERO REGISTRATION NUMBER

CRD42016041301.

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.

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.

A mild ovarian stimulation strategy in women with poor ovarian reserve undergoing IVF: a multicenter randomized non-inferiority trial

STUDY QUESTION

In subfertile women with poor ovarian reserve undergoing IVF does a mild ovarian stimulation strategy lead to comparable ongoing pregnancy rates in comparison to a conventional ovarian stimulation strategy?

SUMMARY ANSWER

A mild ovarian stimulation strategy in women with poor ovarian reserve undergoing IVF leads to similar ongoing pregnancy rates as a conventional ovarian stimulation strategy.

WHAT IS KNOWN ALREADY

Women diagnosed with poor ovarian reserve are treated with a conventional ovarian stimulation strategy consisting of high-dose gonadotropins and pituitary downregulation with a long mid-luteal start GnRH-agonist protocol. Previous studies comparing a conventional strategy with a mild ovarian stimulation strategy consisting of low-dose gonadotropins and pituitary downregulation with a GnRH-antagonist have been under powered and their effectiveness is inconclusive.

STUDY DESIGN, SIZE, DURATION

This open label multicenter randomized trial was designed to compare one cycle of a mild ovarian stimulation strategy consisting of low-dose gonadotropins (150 IU FSH) and pituitary downregulation with a GnRH-antagonist to one cycle of a conventional ovarian stimulation strategy consisting of high-dose gonadotropins (450 IU HMG) and pituitary downregulation with a long mid-luteal GnRH-agonist in women of advanced maternal age and/or women with poor ovarian reserve undergoing IVF between May 2011 and April 2014.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Couples seeking infertility treatment were eligible if they fulfilled the following inclusion criteria: female age ≥35 years, a raised basal FSH level >10 IU/ml irrespective of age, a low antral follicular count of ≤5 follicles or poor ovarian response or cycle cancellation during a previous IVF cycle irrespective of age. The primary outcome was ongoing pregnancy rate per woman randomized. Analyses were on an intention-to-treat basis. We randomly assigned 195 women to the mild ovarian stimulation strategy and 199 women to the conventional ovarian stimulation strategy.

MAIN RESULTS AND THE ROLE OF CHANCE

Ongoing pregnancy rate was 12.8% (25/195) for mild ovarian stimulation versus 13.6% (27/199) for conventional ovarian stimulation leading to a risk ratio of 0.95 (95% CI: 0.57-1.57), representing an absolute difference of -0.7% (95% CI: -7.4 to 5.9). This 95% CI does not extend below the predefined threshold of 10% for inferiority. The duration of ovarian stimulation was significantly lower in the mild ovarian stimulation strategy than in the conventional ovarian stimulation strategy (mean difference -1.2 days, 95% CI: -1.88 to -0.62). Also, a significantly lower amount of gonadotropins was used in the mild simulation strategy, with a mean difference of 3135 IU (95% CI: -3331 to -2940).

LIMITATIONS, REASONS FOR CAUTION

A limitation of our study was the lack of data concerning the cryopreservation of surplus embryos, so we are not informed on cumulative pregnancy rates. Another limitation is that we were not able to follow up on the ongoing pregnancies in all centers, so we are not informed on live birth rates.

WIDER IMPLICATIONS OF THE FINDINGS

The results are directly applicable in daily clinical practice and may lead to considerable cost savings as high dosages of gonadotropins are not necessary in women with poor ovarian reserve undergoing IVF. A health economic analysis of our data planned to test the hypothesis that mild ovarian stimulation strategy is more cost-effective than the conventional ovarian stimulation strategy is underway.

STUDY FUNDING/COMPETING INTERESTS

This study was supported by NUFFIC scholarship (the Netherlands) and STDF short-term fellowship (Egypt).

TRIAL REGISTRATION NUMBER

NTR2788 (Trialregister.nl).

TRIAL REGISTER DATE

01 March 2011.

DATE OF FIRST PATIENT'S ENROLMENT

May 2011.