Aromatase inhibitors for ovulation induction and ovarian stimulation

Hormonal Therapies before in vitro fertilization in women with endometriosis: The Minotaur's Labyrinth and the Ariadne's Thread

Endometriosis-related infertility is one of the most debated topics in reproductive medicine. In recent years, prolonged pre-cycle hormonal regimens gained attention as a mean of improving the assisted reproduction technologies (ART) success rates in endometriosis patients. GnRH agonists, dienogest, medroxyprogesterone acetate, and aromatase inhibitors are the most studied medications. Conflicting results and a high risk of bias exist in almost all of the conducted studies in the field. However, current evidence suggests that pre-cycle treatment with GnRH agonists may be beneficial for patients with stage III/IV endometriosis. Dienogest and medroxyprogesterone acetate-based progestin-primed ovarian stimulation protocol was shown to be comparable to the prolonged GnRH agonists protocol. Finally, aromatase inhibitors seem to be of limited benefit to the assisted reproductive outcomes of endometriosis patients. Although it is challenging to draw any clinical conclusions, pre-cycle hormonal treatments seem to be best indicated in endometriosis patients who had previously failed ART treatment.

Aromatase inhibitors (letrozole) for ovulation induction in infertile women with polycystic ovary syndrome

BACKGROUND

Polycystic ovary syndrome (PCOS) is the most common cause of infrequent periods (oligomenorrhoea) and absence of periods (amenorrhoea). It affects about 5% to 20% of women worldwide and often leads to anovulatory infertility. Aromatase inhibitors (AIs) are a class of drugs that were introduced for ovulation induction in 2001. Since about 2001 clinical trials have reached differing conclusions as to whether the AI, letrozole, is at least as effective as the first-line treatment clomiphene citrate (CC), a selective oestrogen receptor modulator (SERM).

OBJECTIVES

To evaluate the effectiveness and safety of AIs (letrozole) (with or without adjuncts) compared to SERMs (with or without adjuncts) for infertile women with anovulatory PCOS for ovulation induction followed by timed intercourse or intrauterine insemination.

SEARCH METHODS

We searched the following sources, from their inception to 4 November 2021, to identify relevant randomised controlled trials (RCTs): the Cochrane Gynaecology and Fertility Group Specialised Register, CENTRAL, MEDLINE, Embase and PsycINFO. We also checked reference lists of relevant trials, searched the trial registers and contacted experts in the field for any additional trials. We did not restrict the searches by language or publication status.

SELECTION CRITERIA

We included all RCTs of AIs used alone or with other medical therapies for ovulation induction in women of reproductive age with anovulatory PCOS.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected trials, extracted the data and assessed risks of bias using RoB 1. We pooled trials where appropriate using a fixed-effect model to calculate odds ratios (ORs) and 95% confidence intervals (CIs) for most outcomes, and risk differences (RDs) for ovarian hyperstimulation syndrome (OHSS). The primary outcomes were live birth rate and OHSS rate. Secondary outcomes were clinical pregnancy, miscarriage and multiple pregnancy rates. We assessed the certainty of the evidence for each comparison using GRADE methods.

MAIN RESULTS

This is a substantive update of a previous review; of six previously included trials, we excluded four from this update and moved two to 'awaiting classification' due to concerns about validity of trial data. We included five additional trials for this update that now includes a total of 41 RCTs (6522 women). The AI, letrozole, was used in all trials. Letrozole compared to SERMs with or without adjuncts followed by timed intercourse Live birth rates were higher with letrozole (with or without adjuncts) compared to SERMs followed by timed intercourse (OR 1.72, 95% CI 1.40 to 2.11; I2 = 0%; number needed to treat for an additional beneficial outcome (NNTB) = 10; 11 trials, 2060 participants; high-certainty evidence). This suggests that in women with a 20% chance of live birth using SERMs, the live birth rate in women using letrozole with or without adjuncts would be 27% to 35%. There is high-certainty evidence that OHSS rates are similar with letrozole or SERMs (0.5% in both arms: risk difference (RD) -0.00, 95% CI -0.01 to 0.01; I2 = 0%; 10 trials, 1848 participants; high-certainty evidence). There is evidence for a higher pregnancy rate in favour of letrozole (OR 1.69, 95% CI 1.45 to 1.98; I2 = 0%; NNTB = 10; 23 trials, 3321 participants; high-certainty evidence). This suggests that in women with a 24% chance of clinical pregnancy using SERMs, the clinical pregnancy rate in women using letrozole with or without adjuncts would be 32% to 39%. There is little or no difference between treatment groups in the rate of miscarriage per pregnancy (25% with SERMs versus 24% with letrozole: OR 0.94, 95% CI 0.66 to 1.32; I2 = 0%; 15 trials, 736 participants; high-certainty evidence) and multiple pregnancy rate (2.2% with SERMs versus 1.6% with letrozole: OR 0.74, 95% CI 0.42 to 1.32; I2 = 0%; 14 trials, 2247 participants; high-certainty evidence). However, a funnel plot showed mild asymmetry, indicating that some trials in favour of SERMs might be missing.  Letrozole compared to laparoscopic ovarian drilling (LOD) One trial reported very low-certainty evidence that live birth rates may be higher with letrozole compared to LOD (OR 2.07, 95% CI 0.99 to 4.32; 1 trial, 141 participants; very low-certainty evidence). This suggests that in women with a 22% chance of live birth using LOD with or without adjuncts, the live birth rate in women using letrozole with or without adjuncts would be 24% to 47%. No trial reported OHSS rates. Due to the low-certainty evidence we are uncertain if letrozole improves pregnancy rates compared to LOD (OR 1.47, 95% CI 0.95 to 2.28; I² = 0%; 3 trials, 367 participants; low-certainty evidence). This suggests that in women with a 29% chance of clinical pregnancy using LOD with or without adjuncts, the clinical pregnancy rate in women using letrozole with or without adjuncts would be 28% to 45%. There seems to be no evidence of a difference in miscarriage rates per pregnancy comparing letrozole to LOD (OR 0.65, 95% CI 0.22 to 1.92; I² = 0%; 3 trials, 122 participants; low-certainty evidence). This also applies to multiple pregnancies (OR 3.00, 95% CI 0.12 to 74.90; 1 trial, 141 participants; very low-certainty evidence).

AUTHORS' CONCLUSIONS

Letrozole appears to improve live birth rates and pregnancy rates in infertile women with anovulatory PCOS, compared to SERMs, when used for ovulation induction, followed by intercourse. There is high-certainty evidence that OHSS rates are similar with letrozole or SERMs. There was high-certainty evidence of no difference in miscarriage rate and multiple pregnancy rate. We are uncertain if letrozole increases live birth rates compared to LOD. In this update, we added good quality trials and removed trials with concerns over data validity, thereby upgrading the certainty of the evidence base.

Aromatase inhibitors (letrozole) for subfertile women with polycystic ovary syndrome

BACKGROUND

Polycystic ovary syndrome (PCOS) is the most common cause of infrequent periods (oligomenorrhoea) and absence of periods (amenorrhoea). It affects about 4% to 8% of women worldwide and often leads to anovulatory subfertility. Aromatase inhibitors (AIs) are a class of drugs that were introduced for ovulation induction in 2001. Since about 2001 clinical trials have reached differing conclusions as to whether the AI letrozole is at least as effective as the first-line treatment clomiphene citrate (CC).

OBJECTIVES

To evaluate the effectiveness and safety of aromatase inhibitors for subfertile women with anovulatory PCOS for ovulation induction followed by timed intercourse or intrauterine insemination (IUI).

SEARCH METHODS

We searched the following sources from inception to November 2017 to identify relevant randomised controlled trials (RCTs): the Cochrane Gynaecology and Fertility Group Specialised Register, the Cochrane Central Register of Controlled Trials, MEDLINE, Embase, PsycINFO, Pubmed, LILACS, Web of Knowledge, the World Health Organization (WHO) clinical trials register and Clinicaltrials.gov. We also searched the references of relevant articles. We did not restrict the searches by language or publication status.

SELECTION CRITERIA

We included all RCTs of AIs used alone or with other medical therapies for ovulation induction in women of reproductive age with anovulatory PCOS.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected trials, extracted the data and assessed risks of bias. We pooled studies where appropriate using a fixed-effect model to calculate odds ratios (ORs) and 95% confidence intervals (CIs) for most outcomes, and risk differences (RDs) for ovarian hyperstimulation syndrome (OHSS). The primary outcomes were live birth and OHSS. Secondary outcomes were clinical pregnancy, miscarriage and multiple pregnancy. We assessed the quality of the evidence for each comparison using GRADE methods.

MAIN RESULTS

This is a substantive update of a previous review. We identified 16 additional studies for the 2018 update. We include 42 RCTs (7935 women). The aromatase inhibitor letrozole was used in all studies.Letrozole compared to clomiphene citrate (CC) with or without adjuncts followed by timed intercourseLive birth rates were higher with letrozole (with or without adjuncts) compared to clomiphene citrate (with our without adjuncts) followed by timed intercourse (OR 1.68, 95% CI 1.42 to 1.99; 2954 participants; 13 studies; I² = 0%; number needed to treat for an additional beneficial outcome (NNTB) = 10; moderate-quality evidence). There is high-quality evidence that OHSS rates are similar with letrozole or clomiphene citrate (0.5% in both arms: risk difference (RD) -0.00, 95% CI -0.01 to 0.00; 2536 participants; 12 studies; I² = 0%; high-quality evidence). There is evidence for a higher pregnancy rate in favour of letrozole (OR 1.56, 95% CI 1.37 to 1.78; 4629 participants; 25 studies; I² = 1%; NNTB = 10; moderate-quality evidence). There is little or no difference between treatment groups in the rate of miscarriage by pregnancy (20% with CC versus 19% with letrozole; OR 0.94, 95% CI 0.70 to 1.26; 1210 participants; 18 studies; I² = 0%; high-quality evidence) and multiple pregnancy rate (1.7% with CC versus 1.3% with letrozole; OR 0.69, 95% CI 0.41 to 1.16; 3579 participants; 17 studies; I² = 0%; high-quality evidence). However, a funnel plot showed mild asymmetry, indicating that some studies in favour of clomiphene might be missing.Letrozole compared to laparoscopic ovarian drillingThere is low-quality evidence that live birth rates are similar with letrozole or laparoscopic ovarian drilling (OR 1.38, 95% CI 0.95 to 2.02; 548 participants; 3 studies; I² = 23%; low-quality evidence). There is insufficient evidence for a difference in OHSS rates (RD 0.00, 95% CI -0.01 to 0.01; 260 participants; 1 study; low-quality evidence). There is low-quality evidence that pregnancy rates are similar (OR 1.28, 95% CI 0.94 to 1.74; 774 participants; 5 studies; I² = 0%; moderate-quality evidence). There is insufficient evidence for a difference in miscarriage rate by pregnancy (OR 0.66, 95% CI 0.30 to 1.43; 240 participants; 5 studies; I² = 0%; moderate-quality evidence), or multiple pregnancies (OR 3.00, 95% CI 0.12 to 74.90; 548 participants; 3 studies; I² = 0%; low-quality evidence).Additional comparisons were made for Letrozole versus placebo, Selective oestrogen receptor modulators (SERMS) followed by intrauterine insemination (IUI), follicle stimulating hormone (FSH), Anastrozole, as well as dosage and administration protocols. There is insufficient evidence for a difference in either group of treatment due to a limited number of studies. Hence more research is necessary.

AUTHORS' CONCLUSIONS

Letrozole appears to improve live birth and pregnancy rates in subfertile women with anovulatory polycystic ovary syndrome, compared to clomiphene citrate. There is high-quality evidence that OHSS rates are similar with letrozole or clomiphene citrate. There is high-quality evidence of no difference in miscarriage rates or multiple pregnancy rates. There is low-quality evidence of no difference in live birth and pregnancy rates between letrozole and laparoscopic ovarian drilling, although there were few relevant studies. For the 2018 update, we added good-quality trials, upgrading the quality of the evidence.

Ovarian Hyperstimulation Syndrome: A Narrative Review of Its Pathophysiology, Risk Factors, Prevention, Classification, and Management

Ovarian hyperstimulation syndrome (OHSS) is a serious complication of ovulation induction that usually occurs after gonadotropin stimulation, followed by human chorionic gonadotropin administration, for infertility treatment. The existing knowledge about the pathophysiology, risk factors, and primary and secondary methods for the prevention of OHSS is reviewed in this manuscript. The clinical manifestations and characteristics of mild, moderate, severe, and critical forms of the syndrome are defined. The methods of handling affected cases as outpatient or in-hospital management methods as well as indications for hospitalization are summarized in this review. The clinical and biochemical routes of assessing and monitoring hospitalized patients with OHSS, various drugs and medical treatment strategies including indications for aspiration of the ascitic fluid and pleural effusion, and also rare indications for surgery are briefly explained in this article. Severe OHSS, which two decades ago was considered an iatrogenic life-threatening condition, can now be effectively prevented or managed during the early stages. An OHSS-free clinic can be established nowadays by carefully considering the endocrinology of ovulation and using appropriate and dose-adjusted pharmaceutical agents, which are summarized and discussed in this review.

PCOS and pregnancy: a review of available therapies to improve the outcome of pregnancy in women with polycystic ovary syndrome

INTRODUCTION

Polycystic ovary syndrome (PCOS) is a common cause of female infertility affecting multiple aspects of a women's health.

AREAS COVERED

The aim of this review is to summarize the existing evidence on the treatment of PCOS patients and to examine the actual available therapies to overcome the problem of infertility and improve the outcome of pregnancy. We analyse different treatment strategies such as lifestyle modification, bariatric surgery, insulin sensitizing agents, inositol, clomiphene citrate (CC), aromatase inhibitors, gonadotrophins, laparoscopic ovarian drilling, and assisted reproductive techniques (ART).

EXPERT COMMENTARY

Lifestyle modification is the best initial management for obese PCOS patients seeking pregnancy and insulin sensitizing agents seem to have an important role in treating insulin resistance. Up to now, CC maintains a central role in the induction of ovulation and it has been confirmed as the first-line treatment; the use of gonadotrophins is considered the second-line in CC resistant patients; laparoscopic ovarian drilling is an alternative to gonadotrophins in patients who need laparoscopy for another reason. However, in anovulatory patients, ART represents the only possible alternative to obtain pregnancy. Larger and well-designed studies are needed to clarify the best way to improve the outcome of pregnancy in PCOS women.

Aromatase Inhibitors for Endometriosis-Associated Infertility; Do We Have Sufficient Evidence?

Orally active aromatase inhibitors (AIs) have gained attention for treatment of infertile women with endometriosis in whom aromatase p450 is aberrantly expressed. This review aimed to critically appraise and summarize the available evidence concerning the use of AIs for management of endometriosis-associated infertility. PubMed was searched to May 2015 with the following key words: endometriosis, infertility and aromatase. Priority was given for randomized controlled trials (RCTs) followed by other study designs. Main outcome measures were as follows: rates of clinical pregnancy, miscarriage and live birth as well as endocrine outcomes. Eighty-two abstracts were screened and six original articles were included. A RCT demonstrated that post-operative letrozole treatment did not improve spontaneous pregnancy rate. Another RCT reported no superiority of letrozole superovulation over clomiphene citrate (each combined with intrauterine insemination) in minimalmild endometriosis and previous laparoscopic treatment. Anastrozole significantly inhibited the growth of endometriotic cells and their estrogen production in culture. In assisted reproductive technology (ART) cycles, dual suppression (Agonist/anastrozole) was tested in a pilot study with a pregnancy rate of 45% however, high pregnancy loss (30%) occurred. A retrospective study showed that letrozole may improve endometrial receptivity in endometriotic patients undergoing in vitro fertilization (IVF). An opposite view from an in vitro study showed lower estradiol production and aromatase expression in cultured granulosa cells from endometriotic women undergoing IVF and marked reduction under letrozole. In conclusion, current evidence is limited. More trials are warranted to enhance our knowledge and provide a clear and unequivocal evidence to guide our clinical management of infertile women with endometriosis using AIs.

Orexin Decreases Aromatase Gene Expression in The Hypothalamus of Androgenized Female Rats

BACKGROUND

Orexin is a hypothalamic orexigenic neuropeptide, which third cerebral injection of it mainly exerts inhibitory effects on reproductive functions. It increases significantly the Aromatase (Cyp19) gene expression in the hypothalamus of male rats. Aromatase is an enzyme which converts androgens to estradiol in the hypothalamus of rats. Prenatal or neonatal exposure of females to testosterone masculinizes the pattern of Cyp19 mRNA levels in adulthood. In the present study the effects of central injections of orexin-A on hypothalamic Cyp19 gene expression of adult female rats were investigated, while they had been androgenized on third day of postnatal life.

MATERIALS AND METHODS

In this experimental study, twenty female Wistar rats received subcutaneous injections of testosterone propionate (50 µg/100 µl) on their third day of postnatal life. Adult androgenized rats weighing 180-220 g, received either 3 µl saline or one of 2, 4 or 8 µg/3 µl concentration of orexin via third cerebral ventricle. Five non-androgenized rats, as control group, received intra cerebral ventricle (ICV) injection of 3 µl saline. The hypothalamuses were dissected out and mean Cyp19 mRNA levels were determined by semi-quantitative real time-polymerase chain reaction (PCR) method. Data were analyzed by unpaired t test and one-way ANOVA using SPSS software, version 16.

RESULTS

Mean relative Cyp19 mRNA level was significantly increased in the hypothalamus of androgenized compared to non-androgenized female rats. Central injec- tions of 2, 4 or 8 µg/3 µl orexin decreased significantly the hypothalamic Cyp19 mRNA level of androgenized rats compared to androgenized-control groups.

CONCLUSION

The results suggested that the orexin may exert inhibitory effects on the gene expression of Cyp19 in the hypothalamus of neonatal androgenized female rats in adulthood.

Prevention of Ovarian Hyperstimulation Syndrome: A Review

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

Minimal stimulation using gonadotropin combined with clomiphene citrate or letrozole for intrauterine insemination

PURPOSE

To evaluate the efficacy of minimal stimulation using discretely administered gonadotropin combined with clomiphene citrate (CC) or letrozole (LTZ) for intrauterine insemination (IUI) cycles.

MATERIALS AND METHODS

Total 257 IUI cycles from 158 infertile couples were assessed. A CC dose of 100 mg/day (n=126 cycles) or a LTZ dose of 5 mg/day (n=131 cycles) was administered on days 3-5 of the menstrual cycle for 5 days. Each group received human menopausal gonadotropin at a dose of 150 IU by two or three alternative day: CC combined with alternate-day regimen for 2 or 3 days (CC+300, n=37; CC+450, n=89) and LTZ combined with alternate-day regimen for 2 or 3 days (LTZ+300, n=36; LTZ+450, n=95).

RESULTS

The clinical pregnancy rate was comparable between the CC and LTZ groups (18.3% vs. 13.0%, p=0.243). The clinical pregnancy rate also showed no significant difference among the 4 groups (21.6% vs. 16.9% vs. 11.1% vs. 12.6%, p=0.507). The multiple pregnancy rate was significantly higher in LTZ compared to CC group (37.5% vs. 8.7%, p=0.028) and in the LTZ+450 compared to CC+450 group (50% vs. 13.3%, p=0.038). Overall, there were 15 cases of ovarian hyperstimulation syndrome (OHSS), with the prevalence being significantly lower in the LTZ compared to CC group (1.5% vs. 10.3%, p=0.003). OHSS was more prevalent in the CC+450 compared to the LTZ+450 group (12.4% vs. 1.1%, p=0.002).

CONCLUSION

Our findings suggest that minimal stimulation using two alternate-day gonadotropin with LTZ decreases the development of OHSS and multiple pregnancies, while maintaining comparable pregnancy rates in IUI cycles.

Clinical use of fertility agents and risk of breast cancer: a recent update for an old problem

PURPOSE OF REVIEW

Female infertility is today a very common, expanding problem and therefore restoring fertility strategies are increasing in the last few years. An association between ovarian stimulation and breast cancer risk has been hypothesized, but the question has not yet been clarified.

RECENT FINDINGS

In the last 2 years, many important studies have been published on this topic. A lot of new combinations of drugs are in experimentation and other recent drugs are already in current use, such as aromatase inhibitors. Furthermore, the data from older studies were investigated by two recent meta-analyses.

SUMMARY

Infertility affects many couples in western countries and the use of fertility stimulation techniques is widespread in the last few years, determining personal anxiety, social costs, and organizing difficulties. It is well known that one of the most important causative agents for the development of breast cancer is the proliferative activity of endogenous and exogenous female hormones. Therefore, it seems appropriate to investigate the risk of breast cancer derived from the use of hormonal therapies in infertile women. The final clarification of this question is very important so that all women can realize their dream of having children, with the certainty of not being exposed to an increased risk of breast cancer.

Ovarian stimulation for IVF: mild approaches

In contrast to current approaches, the aim of mild stimulation is to develop safer and more patient-friendly protocols in which the risks of the treatment as a whole are minimized. Mild stimulation is defined as the method when exogenous gonadotropins are administered at lower doses, and/or for a shorter duration in GnRH antagonist co-treated cycles, or when oral compounds (antiestrogens, aromatase inhibitors) are used for ovarian stimulation for IVF, with the aim of limiting the number of oocytes obtained to fewer than eight. In this chapter we discuss the relevant physiology of follicle development, the development of milder stimulation protocols, the implications of mild stimulation, the current state of affairs, and future developments.

Aromatase inhibitors for subfertile women with polycystic ovary syndrome

BACKGROUND

Polycystic ovary syndrome (PCOS) is the most common cause of infrequent periods (oligomenorrhoea) and absence of periods (amenorrhoea). It affects about 4% to 8% of women worldwide and often leads to anovulatory subfertility. Aromatase inhibitors (AIs) are a novel class of drugs that were introduced for ovulation induction in 2001. Over the last ten years clinical trials have reached differing conclusions as to whether the AI letrozole is at least as effective as the first-line treatment clomiphene citrate (CC).

OBJECTIVES

To evaluate the effectiveness and safety of aromatase inhibitors for subfertile women with anovulatory PCOS.

SEARCH METHODS

We searched the following sources from inception to 24/10/2013 to identify relevant randomised controlled trials (RCTs): the Menstrual Disorders and Subfertility Group Specialised Register, the Cochrane Central Register of Controlled Trials, MEDLINE, EMBASE, PsycINFO, Pubmed, LILACS, Web of Knowledge, the World Health Organisation (WHO) clinical trials register and Clinicaltrials.gov. Furthermore, we manually searched the references of relevant articles.The search was not restricted by language or publication status.

SELECTION CRITERIA

We included all RCTs of aromatase inhibitors used alone or with other medical therapies for ovulation induction in women of reproductive age with anovulatory PCOS.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected trials, extracted the data and assessed trial quality. Studies were pooled where appropriate using a fixed effect model to calculate pooled odds ratios (ORs) and 95% confidence intervals (CIs) for most outcomes and risk differences (RDs) for ovarian hyperstimulation syndrome (OHSS). The primary outcomes were live birth and OHSS. Secondary outcomes were pregnancy, miscarriage and multiple pregnancy. The quality of the evidence for each comparison was assessed using GRADE methods.

MAIN RESULTS

We included 26 RCTs (5560 women). In all studies the aromatase inhibitor was letrozole. Live birth (12 RCTs) One RCT compared letrozole with placebo in women who were clomiphene resistant and the results were inconclusive (OR 3.17, 95% CI 0.12 to 83.17, n=36)Nine RCTs compared letrozole with clomiphene citrate (with or without adjuncts) followed by timed intercourse. The birth rate was higher in the letrozole group (OR 1.63, 95% CI 1.31 to 2.03, n=1783, I²=3%)Two RCTs compared letrozole with laparoscopic ovarian drilling. There was no evidence of a difference between the groups in live birth rate (OR 1.19, 95% CI 0.76 to 1.86, n=407, I²=0%) OHSS (16 RCTs) There was no evidence of a difference in OHSS rates when letrozole was compared with placebo (one RCT, n=36), clomiphene citrate (with or without adjuncts) followed by timed intercourse (nine RCTs, n=2179), clomiphene citrate (with or without adjuncts) followed by intrauterine insemination (IUI) (two RCTs, n=1494), laparoscopic ovarian drilling (one RCT, n=260) or anastrozole (one RCT, n=220). Events were absent or very rare, and no study had more than 2 cases of OHSS. Clinical pregnancy (25 RCTs) One RCT compared letrozole versus placebo in women who were clomiphene resistant and the results were inconclusive (OR 3.17, 95% CI 0.12 to 83.17, n=36)Fourteen RCTs compared letrozole versus clomiphene citrate (with or without adjuncts) followed by timed intercourse. The pregnancy rate was higher in the letrozole group (OR 1.32, 95% CI 1.09 to 1.60, n=2066, I²=25%)Three RCTs compared letrozole versus clomiphene citrate (with or without adjuncts) followed by IUI. The pregnancy rate was higher in the letrozole group (OR 1.71, 95% CI 1.30 to 2.25, n=1597)Three RCTs compared letrozole versus laparoscopic ovarian drilling. There was no evidence of a difference in the clinical pregnancy rate (OR 1.14, 95% CI 0.80 to 1.65, n=553, I²=0%)Two RCTs compared letrozole versus anastrozole, one RCT compared a five day versus a 10 day administration protocol for letrozole and another RCT compared 5 mg of letrozole versus 7.5 mg of letrozole. There was no evidence of a difference in the clinical pregnancy rate in these comparisons.The quality of the evidence was rated as low for live birth and pregnancy outcomes. The reasons for downgrading the evidence were poor reporting of study methods, possible publication bias and the tendency for studies that reported live birth to report higher clinical pregnancy rates in the letrozole group than studies that failed to report live birth (suggesting that results might be somewhat less favourable to letrozole if all studies reported live birth).

AUTHORS' CONCLUSIONS

Letrozole appears to improve live birth and pregnancy rates in subfertile women with anovulatory PCOS, compared to clomiphene citrate. The quality of this evidence is low and findings should be regarded with some caution. There appears to be no difference in effectiveness between letrozole and laparoscopic ovarian drilling, though there were few relevant studies. OHSS was a very rare event, with no occurrences in most studies.

Fertility management in the PCOS population: results of a web-based survey at IVF-worldwide.com

PURPOSE

To identify the leading treatment strategies for infertile women with PCOS on an international scale.

METHODS

A retrospective evaluation using the results of a web-based survey, (IVF-Worldwide ( www.IVF-worldwide.com ), posted from 1 to 30 September 2010 was performed. Binomial confidence intervals for proportions were calculated by the modified Wald method with significance defined as P < 0.05 using a DataStar software package (DataStar, Waltham, MA, USA). Incomplete surveys were excluded from the analysis.

RESULTS

The results from 262 centers in 68 nations were obtained. Clomiphene citrate was the clear first choice, 68 %, for PCOS treatment in the respondent group. Eighty-eight percent of respondents utilized ultrasound follicular monitoring when conducting ovulation induction with oral medications. A significant (p < 0.05) proportion of respondents (66 %) did use some BMI cutoff beyond which IVF treatment was not offered. The preferred IVF protocols for PCOS patients were gonadotropin releasing hormone (GnRH) antagonist, 46 %, and GnRH agonist, 51 %. There was heterogeneity of responses observed regarding the management of a patient at very high risk of OHSS.

CONCLUSIONS

While some advances, such as the use of GnRH antagonist regimen in IVF cycles, were relatively underutilized, the survey gives an unfiltered snapshot at the practice patterns of a large number of clinics. Results from this survey may be used by researchers and professional organizations to improve the clinical care of PCOS women suffering with infertility.

Clinical review: The use of aromatase inhibitors for ovulation induction and superovulation

CONTEXT

Anovulation is likely responsible for 20% of female infertility. Although clomiphene citrate remains the first-line therapy for ovulation induction in anovulatory patients who are not estrogen-deficient and to treat unexplained infertility, there remains a discrepancy between ovulation and conception rates with its use, attributed to its antiestrogenic effects on cervical mucus and the endometrium. Alternative agents, including aromatase inhibitors, have been used that have not been associated with these side effects.

EVIDENCE ACQUISITION

A literature search was conducted to specifically explore the use of aromatase inhibitors for ovulation induction and superovulation.

EVIDENCE SYNTHESIS

Recent studies have found that aromatase inhibitors may be safe and useful agents for ovulation induction in patients with polycystic ovarian syndrome as well a treatment option for superovulation in patients with either unexplained infertility or endometriosis.

CONCLUSIONS

Aromatase inhibitors may be an effective alternative treatment to clomiphene citrate for both ovulation induction and superovulation.

Chinese herbal medicine for infertility with anovulation: a systematic review

The aim of this systematic review is to assess the effectiveness and safety of Chinese herbal medicine (CHM) in treatment of anovulation and infertility in women. Eight (8) databases were extensively retrieved. The Chinese electronic databases included VIP Information, CMCC, and CNKI. The English electronic databases included AMED, CINAHL, Cochrane Library, Embase, and MEDLINE(®). Randomized controlled trials using CHM as intervention were included in the study selection. The quality of studies was assessed by the Jadad scale and the criteria referred to Cochrane reviewers' handbook. The efficacy of CHM treatment for infertility with anovulation was evaluated by meta-analysis. There were 692 articles retrieved according to the search strategy, and 1659 participants were involved in the 15 studies that satisfied the selection criteria. All the included trials were done in China. Meta-analysis indicated that CHM significantly increased the pregnancy rate (odds ratio [OR] 3.12, 95% confidence interval [CI] 2.50-3.88) and reduced the miscarriage rate (OR 0.2, 95% CI 0.10-0.41) compared to clomiphene. In addition, CHM also increased the ovulation rate (OR 1.55, 95% CI 1.06-2.25) and improved the cervical mucus score (OR 3.82, 95% CI 1.78-8.21) compared to clomiphene, while there were no significant difference between CHM and clomiphene combined with other medicine. CHM is effective in treating infertility with anovulation. Also, no significant adverse effects were identified for the use of CHM from the studies included in this review. However, owing to the low quality of the studies investigated, more randomized controlled trials are needed before evidence-based recommendation regarding the effectiveness and safety of CHM in the management of infertility with anovulation can be provided.

The use of aromatase inhibitors in in vitro fertilization

The use of aromatase inhibitors (AIs) in IVF patients remains controversial. AIs can be considered for ovulation induction for IVF in women who are normal and poor responders, are at risk of ovarian hyperstimulation syndrome or thrombosis, who have endometriosis, and/or are undergoing fertility preservation procedures as a result of estrogen-dependent cancers, primarily breast and endometrial cancers. Although the biologic plausibility of the capacity of AIs in IVF patients is promising, results should be interpreted with caution, because the efficacy of AIs needs to be proven in randomized trials.

Ovarian stimulation and intrauterine insemination at the quarter centennial: implications for the multiple births epidemic

Ovarian stimulation and intrauterine insemination (OS/IUI), a mainstay of current infertility therapy and a common antecedent to IVF, is a significant driver of the multiple births epidemic. Redress of this challenge, now marking its quarter centennial, will require a rethinking of current practice patterns. Herein we explore prospects for prevention, mitigation, and eventual resolution. We conclude that the multiple births attributable to OS/IUI may not be entirely preventable but that the outlook for their mitigation is promising, if in need of solidification. Specifically, we observe that low-dose (≤ 75 IU) gondotropin, clomiphene, and especially off-label letrozole regimens outperform high-dose (≥ 150 IU) gonadotropin counterparts in the gestational plurality category while maintaining comparable per-cycle pregnancy rates. Accordingly we recommend that, subject to appropriate exceptions, high-dose gonadotropin regimens be used sparingly and that whenever possible they be replaced with emerging alternatives. Finally, we posit that OS/IUI is not likely to be superseded by IVF absent further commoditization and thus greater affordability.

Human chorionic gonadotrophin stimulation test as a predictor of ovarian response and pregnancy in IVF cycles stimulated with GnRH agonist gonadotrophin treatment: a pilot study

BACKGROUND

Recent evidence supports a specific and broad role of androgen produced by theca cells in reproductive physiology. This pilot study evaluated the usefulness of hCG theca stimulation test in predicting ovarian response and pregnancy.

METHODS

Prospective cohort study including 80 infertile women treated with IVF/ICSI. On Day 3 of the menstrual cycle preceding, the first IVF/ICSI cycle a blood sample was drawn to evaluate baseline FSH, estradiol (E(2)), 17-hydroxy-progesterone, androstenedione and testosterone levels. All women then received 250 µg recombinant hCG s.c. and underwent a second blood sampling 24 h after hCG injection to measurement steroid serum levels.

RESULTS

Percentage increment of E(2) but not its precursors was significantly higher in normo-responders and pregnancy cycles than in poor responders and non-pregnancy cycles (P = 0.03 and P = 0.02, respectively) diagnostic accuracy being 67 and 75%, respectively. The percentage increase in E(2) thus still fails in as many as 33 and 25% of patients in predicting ovarian response and pregnancy, respectively. In addition, E(2) concentrations are poorly reproducible and a wide range of variation in all serum steroids investigated-including E(2)-after hCG injection was observed.

CONCLUSIONS

The predictive power of the hCG test is based on E(2) but not androgen response to hCG injection. This test cannot be recommended in routine clinical practice because it is too laborious for screening purposes, shows great variability in the response obtained and its overall accuracy is not better than that reported for other available markers of ovarian reserve. The use of the currently available markers, antral follicle count and anti-Müllerian hormone, is therefore recommended.

Options on fertility preservation in female cancer patients

Infertility following treatment of cancer is a quality of survival's recognized issue and efforts should be made to help young cancer patients retaining their fertility potential. Options to preserve fertility in female patients include well established methods such as shielding to reduce radiation damage to reproductive organs, fertility-sparing surgery and emergency in vitro fertilization after controlled ovarian stimulation, aiming at freezing embryos. Transfer of frozen/thawed embryos today is a clinical routine in fertility clinics worldwide and it has been used for over 25 years. Mature oocytes after ovarian stimulation can also be frozen unfertilized, nevertheless overall pregnancy rates after fertilization of frozen-thawn oocytes are still relatively lower than those with embryo freezing. Remaining fertility preservation options are still in development and include the freezing of immature oocytes aiming at later in vitro maturing and fertilizing them and the cryopreservation of ovarian tissue for future retransplantation or for in vitro growth and maturation of follicles, both still experimental.