Aromatase Inhibition Reduces the Dose of Gonadotropin Required for Controlled Ovarian Hyperstimulation

Evidence based management of patients with endometriosis undergoing assisted conception: British fertility society policy and practice recommendations

Endometriosis is a chronic inflammatory condition in women of reproductive age, which can lead to infertility and pelvic pain. Endometriosis associated infertility is multifactorial in nature adversely affecting each step of the natural reproductive physiology and thereby processes and outcomes of Assisted Reproductive Technology (ART) cycles. These outcomes are further complicated by the subtype of endometriosis, being peritoneal, deep infiltrating and ovarian, which bear negative effects on ovarian reserve, response to stimulation, accessibility for oocyte retrieval, intraoperative safety and endometrial receptivity. There is still a lack of clear guidance about the role of surgery for ovarian endometriosis/endometriomas. This guideline evaluates the evidence of the impact of pelvic endometriosis and endometriomas on the outcome of ART and provides recommendations for management options before and during ART including intra-uterine insemination. Recommendations are made based on the current evidence for the management of patients with endometriosis across each step of ART with the primary aim of improving ART outcomes.

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.

Agents for ovarian stimulation for intrauterine insemination (IUI) in ovulatory women with infertility

BACKGROUND

Intrauterine insemination (IUI), combined with ovarian stimulation (OS), has been demonstrated to be an effective treatment for infertile couples. Several agents for ovarian stimulation, combined with IUI, have been proposed, but it is still not clear which agents for stimulation are the most effective. This is an update of the review, first published in 2007.

OBJECTIVES

To assess the effects of agents for ovarian stimulation for intrauterine insemination in infertile ovulatory women.

SEARCH METHODS

We searched the Cochrane Gynaecology and Fertility Group trials register, CENTRAL, MEDLINE, Embase, PsycINFO, CINAHL and two trial registers from their inception to November 2020. We performed reference checking and contacted study authors and experts in the field to identify additional studies.

SELECTION CRITERIA

We included truly randomised controlled trials (RCTs) that compared different agents for ovarian stimulation combined with IUI for infertile ovulatory women concerning couples with unexplained infertility. mild male factor infertility and minimal to mild endometriosis.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures recommended by Cochrane.

MAIN RESULTS

In this updated review, we have included a total of 82 studies, involving 12,614 women. Due to the multitude of comparisons between different agents for ovarian stimulation, we highlight the seven most often reported here. Gonadotropins versus anti-oestrogens (13 studies) For live birth, the results of five studies were pooled and showed a probable improvement in the cumulative live birth rate for gonadotropins compared to anti-oestrogens (odds ratio (OR) 1.37, 95% confidence interval (CI) 1.05 to 1.79; I² = 30%; 5 studies, 1924 participants; moderate-certainty evidence). This suggests that if the chance of live birth following anti-oestrogens is assumed to be 22.8%, the chance following gonadotropins would be between 23.7% and 34.6%. The pooled effect of seven studies revealed that we are uncertain whether gonadotropins lead to a higher multiple pregnancy rate compared with anti-oestrogens (OR 1.58, 95% CI 0.60 to 4.17; I² = 58%; 7 studies, 2139 participants; low-certainty evidence). Aromatase inhibitors versus anti-oestrogens (8 studies) One study reported live birth rates for this comparison. We are uncertain whether aromatase inhibitors improve live birth rate compared with anti-oestrogens (OR 0.75, CI 95% 0.51 to 1.11; 1 study, 599 participants; low-certainty evidence). This suggests that if the chance of live birth following anti-oestrogens is 23.4%, the chance following aromatase inhibitors would be between 13.5% and 25.3%. The results of pooling four studies revealed that we are uncertain whether aromatase inhibitors compared with anti-oestrogens lead to a higher multiple pregnancy rate (OR 1.28, CI 95% 0.61 to 2.68; I² = 0%; 4 studies, 1000 participants; low-certainty evidence).  Gonadotropins with GnRH (gonadotropin-releasing hormone) agonist versus gonadotropins alone (4 studies) No data were available for live birth. The pooled effect of two studies  revealed that we are uncertain whether gonadotropins with GnRH agonist lead to a higher multiple pregnancy rate compared to gonadotropins alone (OR 2.53, 95% CI 0.82 to 7.86; I² = 0; 2 studies, 264 participants; very low-certainty evidence).  Gonadotropins with GnRH antagonist versus gonadotropins alone (14 studies) Three studies reported live birth rate per couple, and we are uncertain whether gonadotropins with GnRH antagonist improve live birth rate compared to gonadotropins (OR 1.5, 95% CI 0.52 to 4.39; I² = 81%; 3 studies, 419 participants; very low-certainty evidence). This suggests that if the chance of a live birth following gonadotropins alone is 25.7%, the chance following gonadotropins combined with GnRH antagonist would be between 15.2% and 60.3%. We are also uncertain whether gonadotropins combined with GnRH antagonist lead to a higher multiple pregnancy rate compared with gonadotropins alone (OR 1.30, 95% CI 0.74 to 2.28; I² = 0%; 10 studies, 2095 participants; moderate-certainty evidence). Gonadotropins with anti-oestrogens versus gonadotropins alone (2 studies) Neither of the studies reported data for live birth rate. We are uncertain whether gonadotropins combined with anti-oestrogens lead to a higher multiple pregnancy rate compared with gonadotropins alone, based on one study (OR 3.03, 95% CI 0.12 to 75.1; 1 study, 230 participants; low-certainty evidence). Aromatase inhibitors versus gonadotropins (6 studies) Two studies  revealed that aromatase inhibitors may decrease live birth rate compared with gonadotropins (OR 0.49, 95% CI 0.34 to 0.71; I²=0%; 2 studies, 651 participants; low-certainty evidence). This suggests that if the chance of a live birth following gonadotropins alone is 31.9%,  the chance of live birth following aromatase inhibitors would be between 13.7% and 25%. We are uncertain whether aromatase inhibitors compared with gonadotropins lead to a higher multiple pregnancy rate (OR 0.69, 95% CI 0.06 to 8.17; I²=77%; 3 studies, 731 participants; very low-certainty evidence).  Aromatase inhibitors with gonadotropins versus anti-oestrogens with gonadotropins (8 studies) We are uncertain whether aromatase inhibitors combined with gonadotropins improve live birth rate compared with anti-oestrogens plus gonadotropins (OR 0.99, 95% CI 0.3 8 to 2.54;  I² = 69%; 3 studies, 708 participants; very low-certainty evidence). This suggests that if the chance of a live birth following anti-oestrogens plus gonadotropins is 13.8%, the chance following aromatase inhibitors plus gonadotropins would be between 5.7% and 28.9%. We are uncertain of the effect of aromatase inhibitors combined with gonadotropins compared to anti-oestrogens combined with gonadotropins on multiple pregnancy rate (OR 1.31, 95% CI 0.39 to 4.37;  I² = 0%; 5 studies, 901 participants; low-certainty evidence).

AUTHORS' CONCLUSIONS

Based on the available results, gonadotropins probably improve cumulative live birth rate compared with anti-oestrogens (moderate-certainty evidence). Gonadotropins may also improve cumulative live birth rate when compared with aromatase inhibitors (low-certainty evidence). From the available data, there is no convincing evidence that aromatase inhibitors lead to higher live birth rates compared to anti-oestrogens. None of the agents compared lead to significantly higher multiple pregnancy rates. Based on low-certainty evidence, there does not seem to be a role for different combined therapies, nor for adding GnRH agonists or GnRH antagonists in IUI programs.

Potential of Auraptene in Improvement of Oocyte Maturation, Fertilization Rate, and Inflammation in Polycystic Ovary Syndrome Mouse Model

Polycystic ovary with poor-quality oocytes has remained problematic in polycystic ovary syndrome (PCOS) patients. It is well documented that the inflammation and production of reactive oxygen species (ROS) in PCOS ovaries are significantly higher than normal voluntaries. In this study, we hypothesized that auraptene (AUR), as a coumarin derivative with anti-inflammatory properties, may be effective in improvement of oocyte maturation and fertilization rate in PCOS patients. For this purpose, PCOS model was induced in NMRI mice and confirmed by ovarian histopathology observations and hormonal assays. PCOS-induced mice were administrated with AUR (PCOS-AUR) and metformin (PCOS-MET), and their effects on inflammation, apoptosis rate, oocyte maturation, and in vitro fertilization capacity were determined and compared with those normal and PCOS animals treated with sesame oil (PCOS-sesame oil) and no treatment (PCOS). Treatment with AUR and MET decreased the inflammation and apoptosis rates in PCOS mice compared with PCOS animals with no treatment. PCOS-AUR and PCOS-MET oocytes also showed higher intracellular glutathione and lower ROS concentrations compared with PCOS mice, indicating improved oocyte maturation rate. PCOS-AUR and PCOS-MET groups showed higher percentages of expansion rate and MII stage oocytes, and lower rate of abnormal oocytes compared with PCOS with no treatment. The rate of fertilization in the oocytes isolated from PCOS-AUR and PCOS-MET groups was higher than PCOS-sesame oil and PCOS groups. Our findings suggest that AUR can be considered as a potential candidate for improvement of oocyte maturation and fertilization capacity in PCOS patients, comparable to MET.

Letrozole Compared With Clomiphene Citrate for Unexplained Infertility: A Systematic Review and Meta-analysis

OBJECTIVE

To estimate the clinical effectiveness, as determined by positive pregnancy test, of letrozole compared with clomiphene citrate for ovarian stimulation in patients with unexplained infertility.

DATA SOURCES

We conducted a systematic review and meta-analysis of data from electronic databases including Ovid-MEDLINE, EMBASE, Scopus, Cochrane Database of Systematic Reviews, Cochrane Register of Controlled Trials, Database of Abstracts of Reviews of Effects, and ClinicalTrials.gov.

METHODS

We searched for concepts of unexplained infertility, letrozole, clomiphene citrate, and clinical outcomes including pregnancy and live birth. Studies were included if they were randomized controlled trials (RCTs) comparing clomiphene citrate with letrozole in patients with unexplained infertility. Eight RCTs including 2,647 patients with unexplained infertility were included. Primary outcome was positive pregnancy test per patient. Secondary outcomes included positive pregnancy test per cycle, clinical pregnancy, live birth, spontaneous miscarriage, twin gestation, mean serum estradiol (E2), endometrial thickness, and number of dominant follicles. The Cochrane Q test and Higgin's I were used to assess heterogeneity. Random effects models were used to obtain pooled relative risks (RR) and 95% CIs.

TABULATION, INTEGRATION, AND RESULTS

In analysis per patient, there was no significant difference in positive pregnancy test between patients treated with letrozole compared with clomiphene citrate (24% vs 23%, pooled RR 1.08, 95% CI 0.85-1.36). Significant heterogeneity was noted between studies (I=60.8%). There were no significant differences in clinical pregnancy (pooled RR 1.15, 95% CI 0.71-1.85), live birth (pooled RR 0.94, 95% CI 0.83-1.08), spontaneous miscarriage (pooled RR 0.92, 95% CI 0.61-1.38), or twin gestation (pooled RR 0.81, 95% CI 0.39-1.68). Mean serum E2 was significantly lower in the letrozole group than in the clomiphene citrate group.

CONCLUSION

Although limited by heterogeneity, studies of ovarian stimulation in women with unexplained infertility show no difference in clinical outcomes between letrozole and clomiphene citrate.

Intrauterine Insemination: Fundamentals Revisited

Intrauterine insemination (IUI) is an assisted conception technique that involves the deposition of a processed semen sample in the upper uterine cavity, overcoming natural barriers to sperm ascent in the female reproductive tract. It is a cost-effective, noninvasive first-line therapy for selected patients with functionally normal tubes, and infertility due to a cervical factor, anovulation, moderate male factor, unexplained factors, immunological factor, and ejaculatory disorders with clinical pregnancy rates per cycle ranging from 10 to 20%. It, however, has limited use in patients with endometriosis, severe male factor infertility, tubal factor infertility, and advanced maternal age ≥ 35 years. IUI may be performed with or without ovarian stimulation. Controlled ovarian stimulation, particularly with low-dose gonadotropins, with IUI offers significant benefit in terms of pregnancy outcomes compared with natural cycle or timed intercourse, while reducing associated COH complications such as multiple pregnancies and ovarian hyperstimulation syndrome. Important prognostic indicators of success with IUI include age of patient, duration of infertility, stimulation protocol, infertility etiology, number of cycles, timing of insemination, number of preovulatory follicles on the day of hCG, processed total motile sperm > 10 million, and insemination count > 1 × 106 with > 4% normal spermatozoa. Alternative insemination techniques, such as Fallopian tube sperm perfusion, intracervical insemination, and intratubal insemination, provide no additional benefit compared to IUI. A complete couple workup that includes patient history, physical examination, and clinical and laboratory investigations is mandatory to justify the choice in favor of IUI and guide alternative patient management, while individualizing the treatment protocol according to the patient characteristics with a strict cancelation policy to limit multi-follicular development may help optimize IUI pregnancy outcomes.

Sex Differences in Binge Eating: Gonadal Hormone Effects Across Development

Eating disorders are highly sexually differentiated disorders that exhibit a female predominance in risk. Most theories focus on psychosocial explanations to the exclusion of biological/genetic influences. The purpose of this descriptive review is to evaluate evidence from animal and human studies in support of gonadal hormone effects on sex differences in binge eating. Although research is in its nascent stages, findings suggest that increased prenatal testosterone exposure in males appears to protect against binge eating. Although pubertal testosterone may exert additional protective effects, the prenatal period is likely critical for the decreased risk observed in males. By contrast, studies indicate that, in females, it is the lack of prenatal testosterone coupled with the organizational effects of pubertal ovarian hormones that may lead to increased binge eating. Finally, twin data suggest that changes in genetic risk may underlie these hormone influences on sex differences across development.

Can steroidal ovarian suppression during the luteal phase after oocyte retrieval reduce the risk of severe OHSS?

Background

Ovarian stimulation in IVF cycle results in luteal supraphysiological steroid concentrations especially for high response patients. The aim of this study was to evaluate the efficacy of ovarian steroid hormone suppression in luteal phase after oocyte retrieval for preventing severe ovarian hyperstimulation syndrome (OHSS) in high-risk patients with embryo cryopreservation.

Methods

281 patients with high risk of OHSS were enrolled in this study among 4735 infertile women undergoing their first IVF treatment. The subjects were allocated into treatment and control group. The treatment group (n = 161) received letrozole (n = 43), mifepristone (n = 51), cetrotide (n = 39) and three-drug combinations (n = 28) during the luteal phase after oocyte retrieval, respectively. The control group (n = 120) received no medicine. Fertilization rate, good embryo rate, serum steroid concentration, clinical outcome, and incidence of severe OHSS were compared between the two groups.

Results

On days 2, 5 and 8 after oocyte retrieval, serum estradiol levels in the letrozole and three-drug combination therapy group were significantly lower than in the other three groups at the same time (P < 0.001, respectively). There were no significantly difference of serum luteinizing hormone concentration on days 2, 5 and 8 and progesterone concentration on day 8 after oocyte retreival among the five groups (P > 0.05, respectively). Compared with the control group, the incidence of severe OHSS, the paracentesis rate, the duration of hospitalization and the days of luteal phase in each subgroup of treatment groups was not significantly decreased (P > 0.05, respectively).

Conclusions

Our findings indicate that steroidal ovarian suppression in luteal phase after oocyte retrieval seems to be unable to prevent severe OHSS in high-risk patients with embryo cryopreservation.

Use of aromatase inhibitors in practice of gynecology

Purpose

The conversion of androgens into estrogens by aromatase is called aromatization and is inhibited by aromatase inhibitors (AIs). The aim of this article is to evaluate the use of aromatase inhibitors in gynecological diseases such as endometriosis, leiomyoma, estrogen- dependent gynecologic neoplasia and infertility.

Methods

This is a review of literature combined with experience and use of aromatase ınhıbıtors ın practıce of gynecology.

Conclusion

AIs are promising agents in treatment of estrogen dependent disease. However lack of experience, side effects and cost are limiting factors for using these agents in infertility treatment. However there is need for larger, well designed randomized trials to generate robust data in order to establish the true potential of aromatase inhibitors.

Fertility preservation and minimizing reproductive damage in cancer survivors

Recent advances in oncology have helped in the survival and cure of increasing numbers of childhood cancer patients and those during their reproductive age period. This has increased the need to improve existing technology, and prompted the search for new technologies, to minimize the gonadotoxic effects of cancer treatment and preserve human fertility. Conservative surgical approaches for cancer treatment have been widely accepted following progress in early detection of cancer and accumulating long-term outcome safety data. Gonadal suppression to increase resistance to cancer treatment by gonadotropin analogues and sex hormones has been suggested. However, while this is unlikely to be effective in males, there is no general consensus on its success in the female. Fertility preservation options for both male and female patients include cryopreservation of embryos, gametes and gonads. While embryo cryopreservation is a well-established and successful technique, there are several obvious limitations. Gamete cryopreservation is very successful in males (sperm freezing) while still experimental in females (oocyte freezing), with growing evidence suggesting its potential success. Gonadal cryopreservation is still in its early stages of experimental development, both in males (testicular tissue cryopreservation and in vitro spermatogenesis) and female (ovarian tissue cryopreservation and in vitro follicular maturation).

The root of reduced fertility in aged women and possible therapentic options: current status and future perspects

It is well known that maternal ageing not only causes increased spontaneous abortion and reduced fertility, but it is also a high genetic disease risk. Although assisted reproductive technologies (ARTs) have been widely used to treat infertility, the overall success is still low. The main reasons for age-related changes include reduced follicle number, compromised oocyte quality especially aneuploidy, altered reproductive endocrinology, and increased reproductive tract defect. Various approaches for improving or treating infertility in aged women including controlled ovarian hyperstimulation with intrauterine insemination (IUI), IVF/ICSI-ET, ovarian reserve testing, preimplantation genetic diagnosis and screening (PGD/PGS), oocyte selection and donation, oocyte and ovary tissue cryopreservation before ageing, miscarriage prevention, and caloric restriction are summarized in this review. Future potential reproductive techniques for infertile older women including oocyte and zygote micromanipulations, derivation of oocytes from germ stem cells, ES cells, and iPS cells, as well as through bone marrow transplantation are discussed.

Preservation of Fertility in Female Cancer Patients Desiring Future Child Bearing; What is Available and What can be Offered

The aim of this review is to present an overview of available methods for preservation of ovarian function and fertility in female cancer patients who desire to maintain their child-bearing capacity for future pregnancies. A Medline search was conducted. Published articles from American and European studies from 1976 to present were reviewed. The effect of cancer treatment on the ovary, as well as different methods of fertility preservation and their reproductive outcomes are presented. Pregnancy rates vary according to the type of primary malignancy, stage of disease, method of fertility preservation (for example, hormonal therapy, cryopreservation, fertility-sparing surgery), and other confounding factors such as the patient's age, reproductive capacity, status of partnership, and genetic disposition. The highest rates of successful pregnancy were observed with embryo cryopreservation. Today, higher cure rates and longer survival are a result of earlier cancer diagnosis and treatment. In conjunction with the advances in assisted reproduction, the preservation of ovarian function and fertility is a major part of multidisciplinary care that should be offered to any young female patient with cancer. Fertility preservation in young cancer patients raises a number of ethical issues particularly regarding standard versus experimental therapies, and long-term financial cost.

Inhibitory effect of luteolin on estrogen biosynthesis in human ovarian granulosa cells by suppression of aromatase (CYP19)

Inhibition of aromatase, the key enzyme in estrogen biosynthesis, is an important strategy in the treatment of breast cancer. Several dietary flavonoids show aromatase inhibitory activity, but their tissue specificity and mechanism remain unclear. This study found that the dietary flavonoid luteolin potently inhibited estrogen biosynthesis in a dose- and time-dependent manner in KGN cells derived from human ovarian granulosa cells, the major source of estrogens in premenopausal women. Luteolin decreased aromatase mRNA and protein expression in KGN cells. Luteolin also promoted aromatase protein degradation and inhibited estrogen biosynthesis in aromatase-expressing HEK293A cells, but had no effect on recombinant expressed aromatase. Estrogen biosynthesis in KGN cells was inhibited with differing potencies by extracts of onion and bird chili and by four other dietary flavonoids: kaempferol, quercetin, myricetin, and isorhamnetin. The present study suggests that luteolin inhibits estrogen biosynthesis by decreasing aromatase expression and destabilizing aromatase protein, and it warrants further investigation as a potential treatment for estrogen-dependent cancers.

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.

Letrozole in a low-cost in vitro fertilization protocol in intracytoplasmic sperm injection cycles for male factor infertility: A randomized controlled trial

INTRODUCTION

Letrozole, a selective aromatase inhibitor, reduces the total dose of gonadotrophin required for inducing follicular maturation. We evaluated if incorporation of letrozole could be an effective alternative for low-cost in vitro fertilization (IVF) protocol particularly in intracytoplasmic sperm injection (ICSI) cycles where male factor infertility is the sole indication for IVF.

MATERIALS AND METHODS

It is a randomized controlled single-blind trial. 94 women with history of severe male factor infertility were selected. 42 women (study group) received letrozole, 5 mg daily from day 3-7 and recombinant FSH (rFSH) 75IU/day from day 5 continuously till hCG injection. 52 women (control group) underwent continuous stimulation by rFSH (150-225IU/day) from day 2. GnRH-antagonist (Inj. Orgalutran 0.25 ml sub-cutaneous) was started at maximum follicle size of 14 in both groups. Ovulation was triggered by 10,000IU of hCG followed by IVF-ET. Main outcome measures were total dose of rFSH (IU/cycle), terminal E2 (pg/ml), number of mature follicles, number of oocyte retrieved, transferable embryo, endometrial thickness, pregnancy rate and mean expenditure. Statistical analysis is done by using SPSS11.

RESULTS

As compared to control group (1756 ± 75IU), the study group i.e., Let-rFSH received (625 ± 98IU) significantly lower (P = 0.0001) total dose of rFSH. Terminal E2 was significantly lower (P = 0.0001) in study group than control (830 ± 36 vs. 1076 ± 41 pg/ml) with significant increment in endometrial thickness (P = 0.0008) in study group, (9.1 ± 0.32 vs. 8.7 ± 0.69) which maintained an improved pregnancy rate though nonsignificant. The risk of hyperstimulation had significantly (P = 0.01) reduced in study group than control (0 vs. 7).Treatment outcome in all other aspects including pregnancy rate were statistically comparable. Per cycle mean expenditure was reduced by 34% in study group than control.

CONCLUSION

Adjunctive use of letrozole may be an effective mean of low-cost IVF therapy.

Endometrial receptivity defects during IVF cycles with and without letrozole

BACKGROUND

Our aim was to study ways to improve IVF success rates in women with suspected endometrial receptivity defects.

METHODS

We conducted a retrospective cohort study examining the effect of letrozole (aromatase inhibitor) on integrin expression as a marker of endometrial receptivity. We compared IVF outcomes in 97 infertile women who had undergone ανβ3 integrin assessment by immunohistochemistry in mid-luteal endometrial biopsies. Of 79 women undergoing standard IVF, 29 (36.7%) lacked normal integrin expression. Eighteen other women with low integrin were studied after receiving letrozole during early IVF stimulation. An independent set of ανβ3 integrin-negative patients (n = 15) who had undergone repeat endometrial biopsy for integrin testing while taking letrozole were re-evaluated.

RESULTS

Clinical pregnancy and delivery rates were higher in women with normal ανβ3 integrin expression compared with those who were integrin negative [20/50 (40%) versus 4/29 (13.8%); P = 0.02 and 19/50 (38%) versus 2/29 (7%); P < 0.01, respectively]. In 18 women who received letrozole early in IVF, 11 conceived (61.1%; P < 0.001) compared with integrin-negative patients who did not receive letrozole. In integrin-negative women who were rebiopsied on letrozole, 66.7% reverted to normal integrin expression. Positive endometrial aromatase immunostaining using a polyclonal antibody was a common finding in infertile patients compared with controls.

CONCLUSIONS

Lack of endometrial ανβ3 integrin expression is associated with a poor prognosis for IVF that might be improved with letrozole co-treatment. Prospective studies are needed to confirm and extend these findings but the data suggest that aromatase expression may contribute to implantation failure in some women.

Effects of a non-steroidal aromatase inhibitor on ovarian function in cattle

Effects of the non-steroidal aromatase inhibitor letrozole on ovarian function in cattle were determined. The hypothesis that letrozole would arrest growth of the dominant follicle, resulting in emergence of a new follicular wave at a predictable post-treatment interval, was tested. Heifers were assigned randomly to four groups 4 days after follicular ablation (~2½ days after wave emergence) and given intravenous doses of 500 (n = 9), 250 (n = 10), or 125 µg kg–1 (n = 10) letrozole or phosphate-buffered saline (controls; n = 10). Blood was collected and ovarian structures were monitored daily by transrectal ultrasonography. Plasma concentrations of LH and FSH were measured by radioimmunoassay; plasma concentrations of letrozole were determined by high-performance liquid chromatography tandem mass spectrometry. A single intravenous dose of letrozole did not induce regression of the dominant follicle present at the time of treatment, nor did it directly affect FSH release. Conversely, treatment with letrozole increased endogenous concentrations of LH and extended the lifespan of the dominant follicle, which delayed the next FSH surge and subsequent follicular wave emergence. Letrozole continues to have potential as a non-steroidal treatment for controlling ovarian function in cattle.

Role of androgens in the treatment of patients with low ovarian response

The objective of the current report was to provide a summary of knowledge concerning the treatment of women with poor ovarian response with androgens and androgen modulating agents. This involved a review of the literature. The literature search was performed using PubMed. Information concerning the role of androgens and androgen modulating agents in treating women with poor ovarian response is limited. The search of the literature yielded five studies and one case report concerning the treatment of poor responders with androgens. The variations in patient selection, type of androgens employed and the different duration of exposure preclude drawing any definite conclusions. Aromatase inhibitors block the conversion of androgens to oestrogens, thereby promoting an androgen-rich intrafollicular environment. The evidence presented in this review suggests a potential beneficial role for the use of aromatase inhibitors in treating women who have previously experienced failure of standard IVF protocols. The optimal dose and duration of this treatment is yet to be determined. Although the results of studies concerning LH supplementation in poor responders are conflicting, the latest Cochrane review on the use of recombinant LH for ovarian stimulation supports its use in poor responders, based on pooled pregnancy estimates.

A comparison of the effects of clomiphene citrate and the aromatase inhibitor letrozole on superovulation in Asian women with normal ovulatory cycles

OBJECTIVE

To compare the effect of the aromatase inhibitor letrozole and clomiphene citrate (CC) on superovulation in women with normal ovulation.

METHODS

A cross-over randomized study of 22 women with normal ovulation, divided randomly into two equal cohorts, was carried out. Each group of 11 women was randomly allocated to take letrozole or CC for one cycle. After washing out for one cycle, the alternative drug was administered in the subsequent cycle. The number and size of mature follicles, endometrial thickness, and estradiol and progesterone levels were monitored.

RESULTS

The number of mature follicles and estradiol levels on ovulation day were significantly lower in the letrozole group than the CC group (p < 0.05 for both). However, no differences between the two groups in endometrial thickness and pattern were observed. Progesterone levels showed ovulation in all cycles.

CONCLUSIONS

The administration of 50 mg CC on days 3-5 was superior to 2.5 mg letrozole for superovulation induction in women with normal ovulation.

Ovarian stimulation protocols (anti-oestrogens, gonadotrophins with and without GnRH agonists/antagonists) for intrauterine insemination (IUI) in women with subfertility

BACKGROUND

Intrauterine insemination (IUI) combined with ovarian hyperstimulation (OH) has been demonstrated to be an effective form of treatment for subfertile couples. Several ovarian stimulation protocols combined with IUI have been proposed, but it is still not clear which stimulation protocol and which dose is the most cost-effective.

OBJECTIVES

To evaluate ovarian stimulation protocols for intrauterine insemination for all indications.

SEARCH STRATEGY

We searched for all publications which described randomised controlled trials comparing different ovarian stimulation protocols followed by IUI. We searched the Menstrual Disorders and Subfertility Group's Central register of Controlled Trials (CENTRAL). We searched the electronic databases of MEDLINE (January 1966 to present) and EMBASE (1980 to present).

SELECTION CRITERIA

Randomised controlled trials only were considered for inclusion in this review. Trials comparing different ovarian stimulation protocols combined with IUI were selected and reviewed in detail.

DATA COLLECTION AND ANALYSIS

Two independent review authors independently assess trial quality and extracted data.

MAIN RESULTS

Forty three trials involving 3957 women were included. There were 11 comparisons in this review. Pregnancy rates are reported here since results of live birth rates were lacking. Seven studies (n = 556) were pooled comparing gonadotrophins with anti-oestrogens showing significant higher pregnancy rates with gonadotrophins (OR 1.8, 95% CI 1.2 to 2.7). Five studies (n = 313) compared anti-oestrogens with aromatase inhibitors reporting no significant difference (OR 1.2 95% CI 0.64 to 2.1). The same could be concluded comparing different types of gonadotrophins (9 studies included, n = 576). Four studies (n = 391) reported the effect of adding a GnRH agonist which did not improve pregnancy rates (OR 0.98 95% CI 0.6 to 1.6), although it resulted in significant higher multiple pregnancy rates (OR 2.9 95% CI 1.0 to 8). Data of three studies (n = 299) showed no convincing evidence of adding a GnRH antagonist to gonadotrophins (OR 1.5 95% CI 0.83 to 2.8). The results of two studies (n = 297) reported no evidence of benefit in doubling the dose of gonadotrophins (OR 1.2 95% 0.67 to 1.9) although the multiple pregnancy rates and OHSS rates were increased. For the remaining five comparisons only one or none studies were included.

AUTHORS' CONCLUSIONS

Robust evidence is lacking but based on the available results gonadotrophins might be the most effective drugs when IUI is combined with ovarian hyperstimulation. When gonadotrophins are applied it might be done on a daily basis. When gonadotrophins are used for ovarian stimulation low dose protocols are advised since pregnancy rates do not differ from pregnancy rates which result from high dose regimen, whereas the chances to encounter negative effects from ovarian stimulation such as multiples and OHSS are limited with low dose gonadotrophins. Further research is needed for each comparison made.

Potential of aromatase inhibitors for ovulation and superovulation induction in infertile women

For almost half a century, the first-line treatment for ovulation induction in cases of anovulation, unexplained infertility, or mild male factor has been clomifene (clomiphene citrate). Clomifene is an effective and safely used oral agent, but is known to have relatively common antiestrogenic endometrial and cervical mucous adverse effects that could prevent pregnancy in the face of successful ovulation. In addition, there is a significant risk of multiple pregnancies with clomifene compared with natural cycles. These drawbacks are mainly a result of the extended antiestrogenic effect of clomifene as a result of its accumulation in the body (clomifene isomers have a half-life of several days up to few weeks). Because of these problems, we proposed the concept of aromatase inhibition as a new method of ovulation induction that could avoid many of the adverse effects of clomifene. Over the last few years several published studies, both controlled and noncontrolled, compared clomifene and treatment with aromatase inhibitors (AIs), either alone or in combination with gonadotropins, for ovulation induction or augmentation. These studies found AIs as effective as clomifene in inducing ovulation, with the major advantage of absence of any antiestrogenic adverse effects. Several other major advantages of AIs include the lower serum estrogen production per developing follicle resulting in more physiological estrogen levels around the time of ovulation and good pregnancy rates with a lower incidence of multiple pregnancy than with clomifene. When combined with gonadotropins for assisted reproductive technologies, AIs reduce the dose of gonadotropins required for optimal follicle recruitment and improve the response to gonadotropin stimulation in poor responders. Such preliminary evidence suggests that AIs may replace clomifene in the future because of similar efficacy with a reduced adverse-effect profile. However, we believe that definitive studies in the form of randomised controlled trials comparing clomifene with AIs are needed.

Follicular phase dynamics with combined aromatase inhibitor and follicle stimulating hormone treatment

OBJECTIVE

The objective of this study was to evaluate follicular phase parameters during ovarian stimulation with FSH alone or with the aromatase inhibitor letrozole.

METHODS

Two groups of women undergoing intrauterine insemination (IUI): group I (389 patients; mean age 35 +/- 4.3 yr) underwent 630 IUI cycles stimulated with letrozole and FSH; and group II (134 patients; mean age 36.0 +/- 4.6 yr) underwent 166 IUI cycles stimulated with FSH only. Each group was stratified into ovulatory and anovulatory cycles. Patients were monitored by ultrasound for folliculometry and blood sampling for hormonal assay on d 3, 7, 9, or 10 of the cycle, and on the day of human chorionic gonadotropin administration.

RESULTS

Group I had a significantly lower follicular count greater than 10 mm on d 7, greater than 12 mm on d 9 or 10, and greater than 15 mm on the day of human chorionic gonadotropin administration compared to group II (P = 0.006, <0.001, and <0.001, respectively). After stratifying patients by diagnosis, this relationship was maintained only for patients with ovulatory infertility (P = 0.003, <0.001, and <0.001, respectively). Serum estradiol (E2) was significantly lower in the group I ovulatory and anovulatory at the last three monitoring visits (P < 0.001). However, the difference in E2 levels decreased in the preovulatory period with similar E2 levels per mature follicle. No premature preovulatory progesterone rise was observed in either group. However, significantly lower progesterone levels were observed in the second half of the follicular phase in group I (P = 0.02 and <0.001). Endometrial thickness was significantly lower in group I at the second and third visits (P < 0.001, 0.01) but was comparable to group II at the last monitoring visit. Although, the pregnancy rates were similar between the two groups, the multiple pregnancy rate was significantly higher in the FSH-only group (P = 0.039).

CONCLUSION

The addition of letrozole modifies the follicular, hormonal, and endometrial dynamics of FSH-stimulated cycles with possible positive effects on the overall cycle outcome.

Aromatase inhibitors in ovarian stimulation for IVF/ICSI: a pilot study

This prospective randomized pilot study was aimed at investigating the effect of the novel addition of aromatase inhibitors to an ovarian stimulation protocol for IVF or intracytoplasmic sperm injection, on endocrine parameters including serum androgen, oestrogen, progesterone, LH and FSH concentrations. The patients were randomized to receiving letrozole (group A; n = 10), versus no letrozole (group B; n = 10) in an ovarian stimulation protocol with recombinant FSH 150 IU/day starting on day 2 of the cycle, and gonadotrophin-releasing hormone antagonist 0.25 mg/day starting on day 6 of the cycle. Median LH concentrations were significantly higher (P < 0.01) in group A versus group B during letrozole administration. Median serum oestradiol concentrations were lower in group A versus group B, and median serum FSH, testosterone and androstenedione concentrations were higher in group A versus group B, throughout the follicular phase, without reaching significance. Median endometrial thickness was significantly higher (P < 0.05) in group A versus group B on the day of human chorionic gonadotrophin administration. Pregnancies were achieved. This pilot study supports the idea that aromatase inhibitors can contribute to normal potential of implantation and follicular response, without having negative anti-oestrogenic effects.

Comparison of the efficacy of the aromatase inhibitor letrozole and clomiphene citrate as adjuvants to recombinant follicle-stimulating hormone in controlled ovarian hyperstimulation: a prospective, randomized, blinded clinical trial

OBJECTIVE

To study the efficacy of the aromatase inhibitor letrozole as adjuvant to recombinant FSH (rFSH) in controlled ovarian hyperstimulation (COH).

DESIGN

Prospective, randomized, and blinded clinical study.

SETTING

Academic tertiary institute.

PATIENT(S)

Forty-one patients with unexplained infertility undergoing intrauterine insemination (IUI) therapy were randomized to receive either letrozole or clomiphene citrate (CC) as adjuvants to rFSH.

INTERVENTION(S)

From day 3 to 7 of the cycle 2.5 mg/d letrozole or 100 mg/d CC were administrated. All patients received 75 IU rFSH starting on day 7 of stimulation until the day of hCG administration. Ovulation was triggered with recombinant hCG (250 microg) when the leading follicle(s) reached 18 mm in diameter. A single IUI was performed 36 hours later. The luteal phase was supplemented with micronized progesterone vaginally.

MAIN OUTCOME MEASURE(S)

Ovarian stimulation response (E(2) levels and number of follicles) was our primary outcome.

RESULT(S)

There were no differences in demographic characteristics between groups. Although there was a significantly lower peak serum E(2) level in the group receiving letrozole + rFSH compared with CC + rFSH (914 +/- 187 vs. 1,207 +/- 309 pg/mL, respectively; P<.007), there were no differences in the number of mature (>16 mm) preovulatory follicles. A significantly higher endometrial thickness was observed at the time of hCG administration in patients that received letrozole (9.5 +/- 1.5 mm vs. 7.3 +/- 1.1 mm; P=.0001). The clinical pregnancy rate was similar between groups (23.8% vs. 20%, respectively).

CONCLUSION(S)

The aromatase inhibitor letrozole appears to constitute a good alternative to CC in patients with unexplained infertility undergoing gonadotropin-stimulated COH cycles combined with IUI therapy.

Use of an aromatase inhibitor in patients with polycystic ovary syndrome: a prospective randomized trial

OBJECTIVE

To compare the use of an aromatase inhibitor (letrozole) with the use of clomiphene citrate (CC).

DESIGN

Prospective randomized study.

SETTING

An infertility clinic in a university hospital.

PATIENT(S)

Seventy-four consecutive infertile patients with polycystic ovary syndrome were recruited. Thirty-eight patients were randomized to the letrozole group (99 cycles), and the remaining patients were recruited to the CC group (95 cycles).

INTERVENTION(S)

The aromatase inhibitor letrozole (2.5 mg/d) and CC (100 mg/d) were administered orally on days 3-7 of menses.

MAIN OUTCOME MEASURE(S)

Number of follicles, endometrial thickness, E(2) levels on hCG day, and pregnancy rates among both groups.

RESULT(S)

Ovulation occurred in 65.7% (65/99) of letrozole cycles and in 74.7% (71/95) of CC cycles. The median (minimum-maximum) number of follicles sized >15 mm in diameter on the day of hCG administration were 1 (0-4) and 1 (0-5) in the letrozole and CC groups, respectively. On the day of hCG administration, median serum E(2) concentrations in the letrozole and CC groups were statistically significantly different: 189 pg/mL (18-1,581 pg/mL) and 386 pg/mL (27-6,190 pg/mL), respectively. The median serum E(2) concentrations per follicle sized >15 mm in diameter on the day of hCG also statistically significantly differed between the letrozole and CC groups: 160 pg/mL (18-808 pg/mL) and 281 pg/mL (27-2,615 pg/mL), respectively. The median endometrial thickness on the day of hCG did not significantly differ between the CC and letrozole groups; it was 8 mm. Pregnancy was achieved in nine cycles (9.1%) of the letrozole group and in seven cycles (7.4%) of the CC group, which also was not a statistically significant difference.

CONCLUSION(S)

The aromatase inhibitor letrozole may be an acceptable alternative to CC as an ovulation-induction drug in patients with PCOS.

Fertility preservation in young women undergoing breast cancer therapy

Breast cancer accounts for one third of all neoplasms seen in reproductive-age women and affects tens of thousands of women each year in that age group. The adjuvant chemotherapy regimens used for the treatment commonly affect fertility and cause premature ovarian failure. There have been recent advances in the field of fertility preservation, which can allow many of these breast cancer survivors to have children in the future. The most established option is embryo cryopreservation; oocyte cryopreservation can be considered in single women. Both of these approaches require approximately 2 weeks of ovarian stimulation beginning with the onset of the patient's menstrual cycle. Thus, it is crucial that these patients are referred to appropriate assisted reproduction centers as soon as they are diagnosed with breast cancer. Recently developed ovarian stimulation protocols using tamoxifen and letrozole can be used to increase the margin of safety in these patients. When and if a breast cancer patient does not have time to undergo ovarian stimulation prior to chemotherapy, ovarian cryopreservation for future autotransplantation can be offered as the last resort. The benefit of ovarian protection by gonadotropin-releasing hormone analogues is unproven and unlikely, and thus this treatment should not be offered as the sole method of fertility preservation.

Letrozole reduces estrogen and gonadotropin exposure in women with breast cancer undergoing ovarian stimulation before chemotherapy

CONTEXT

Women with breast cancer are not typically offered embryo or oocyte cryopreservation to preserve their fertility before chemotherapy because of the potential risks associated with high estrogen levels arising from ovarian stimulation.

OBJECTIVE

We aimed to determine whether the combination of an aromatase inhibitor with gonadotropin treatment in breast cancer patients produces comparable results to standard in vitro fertilization (IVF), without a significant increase in estradiol levels and delay in the initiation of chemotherapy.

PATIENTS AND METHODS

Stages I-IIIA breast cancer patients (n = 47) received 5 mg/d letrozole and 150-300 IU FSH to cryopreserve embryos or oocytes. Age-matched retrospective controls (n = 56) were selected from women who underwent IVF for tubal disease.

RESULTS

Whereas letrozole and FSH stimulation resulted in significantly lower peak estradiol levels (mean +/- sd 483.4 +/- 278.9 vs. 1464.6 +/- 644.9 pg/ml; P < 0.001) and 44% reduction in gonadotropin requirement, compared with controls, the length of stimulation, number of embryos obtained, and fertilization rates were similar. The human chorionic gonadotropin administration criteria had to be adjusted to 20 mm after letrozole stimulation, compared with 17-18 mm in the controls. The mean delay from surgery to cryopreservation was 38.6 d, with 81% of all patients completing their IVF cycles within 8 wk of surgery.

CONCLUSION

Ovarian stimulation with letrozole and FSH appears to be a cost-effective alternative for fertility preservation in breast cancer patients with reduced estrogen exposure, compared with standard IVF. If patients are referred promptly, they may undergo embryo or oocyte cryopreservation without a delay in chemotherapy.

Preliminary experience with a low-cost stimulation protocol that includes letrozole and human menopausal gonadotropins in normal responders for assisted reproductive technologies

A low-cost stimulation protocol that includes letrozole and hMG in normal responders for assisted reproductive technologies resulted in a satisfactory ongoing pregnancy rate.

Cost-effectiveness of aromatase inhibitor co-treatment for controlled ovarian stimulation

BACKGROUND

To compare the clinical results and the cost-effectiveness of using the aromatase inhibitor, letrozole, in conjunction with FSH and FSH alone for controlled ovarian stimulation (COS) in patients undergoing intrauterine insemination (IUI) for a variety of indications.

METHODS

Four hundred and thirty-two consecutive patients who underwent 872 IUI cycles were included. The study population was composed of two groups. Group I included 308 patients who underwent 589 IUI cycles with letrozole and FSH for the following indications: anovulation (143 cycles), male factor infertility (147 cycles), unexplained infertility (250 cycles), endometriosis (18 cycles) and combined indications (31 cycles). Group II included 124 patients who underwent 283 IUI cycles who received FSH only for the following indications: ovarian factor infertility (82 cycles), male factor infertility (66 cycles), unexplained infertility (114 cycles), endometriosis (13 cycles) and other indications (8 cycles). Main outcome measures included number of mature follicles >16 mm in diameter, dose of FSH used per cycle, clinical pregnancy rate and cost-effectiveness ratio per pregnancy.

RESULTS

FSH dose required for ovarian stimulation was significantly lower when letrozole was used (P < 0.0001). Although a significantly higher number of follicles >16 mm and endometrial thickness at the day of hCG administration (P < 0.0001) were observed in Group II, pregnancy rate per started (14.4 versus 15.9%) and per completed cycles (15.77 versus 18.07%) was the same in Group I and Group II, respectively. IUI cancellation rate was significantly lower with letrozole treatment (P = 0.05%). The cost per cycle was significantly lower in Group I versus Group II (468.93 Can dollars +/- 418.18 versus 1067.28 +/- 921.43; P < 0.0001). The cost-effectiveness ratio was 3249.42 dollars in the letrozole group and 6712.00 dollars in the FSH-only group.

CONCLUSION

A letrozole-FSH combination could be an effective ovarian stimulation protocol in IUI cycles. Such a protocol may be more cost-effective than FSH alone because of the difference of FSH dose and cost. A randomized controlled trial is needed to further substantiate this finding.

A new era in ovulation induction

OBJECTIVE

To evaluate the efficacy of aromatase inhibitors in ovulation induction, superovulation, and IVF.

DESIGN

A literature search was conducted with the key words "aromatase inhibitor," "letrozole," "anastrazole," "ovulation induction," "ovulation," and "superovulation" in MEDLINE, EMBASE, and the Cochrane Database of systematic reviews.

RESULT(S)

Ovulation induction with letrozole is associated with an ovulation rate of 70%-84% and a pregnancy rate of 20%-27% per cycle. In one study, ovulation and pregnancy rates with letrozole seemed to be higher than those of anastrazole. In superovulation, letrozole is associated with few developing follicles and thick endometrium. The use of letrozole for superovulation is associated with a pregnancy rate higher than with the use of clomiphene citrate (CC) (16.7% vs. 5.6%). The addition of letrozole to FSH treatment leads to a decreased FSH requirement. The pregnancy rate for treatment with letrozole and FSH was similar to that for FSH alone.

CONCLUSION(S)

Aromatase inhibitors are as effective as or superior to CC in ovulation induction and in superovulation. Unlike CC, they do not carry an antiestrogenic effect on the endometrium. Given the advantages of aromatase inhibitors, they can be used to replace CC as ovulation-inducing drugs. Their role in IVF remains to be determined.

Aromatase inhibitors: the next generation of therapeutics for endometriosis?

OBJECTIVE AND DESIGN

To review the role of aromatase inhibitors (AIs) in the treatment of endometriosis.

CONCLUSION(S)

Endometriosis is a common estrogen-dependent disorder that can result in substantial morbidity, including pelvic pain, multiple operations, and infertility. Approximately only half of women with endometriosis get pain relief from existing medical or surgical treatments. Medical treatments usually are directed at inhibiting estrogen action or its production from the ovaries and do not address local estrogen biosynthesis by the aromatase enzyme in endometriotic lesions. A single gene encodes aromatase, which is the final enzyme in the estrogen biosynthesis pathway, and its inhibition effectively eliminates estrogen production. The recently introduced highly specific AIs have successfully treated pelvic pain and significantly reduced the lesion size. In premenopausal women, an AI alone may induce ovarian folliculogenesis, and thus AIs are combined with a progestin, a combination oral contraceptive, or a GnRH analogue. The side-effect profile of AIs administered in combination with an oral contraceptive or a progestin is remarkably benign. We review herein the published clinical evidence for the use of AIs in the treatment of endometriosis.

The science behind 25 years of ovarian stimulation for in vitro fertilization

To allow selection of embryos for transfer after in vitro fertilization, ovarian stimulation is usually carried out with exogenous gonadotropins. To compensate for changes induced by stimulation, GnRH analog cotreatment, oral contraceptive pretreatment, late follicular phase human chorionic gonadotropin, and luteal phase progesterone supplementation are usually added. These approaches render ovarian stimulation complex and costly. The stimulation of multiple follicular development disrupts the physiology of follicular development, with consequences for the oocyte, embryo, and endometrium. In recent years, recombinant gonadotropin preparations have become available, and novel stimulation protocols with less detrimental effects have been developed. In this article, the scientific background to current approaches to ovarian stimulation for in vitro fertilization is reviewed. After a brief discussion of the relevant aspect of ovarian physiology, the development, application, and consequences of ovarian stimulation strategies are reviewed in detail.

Review: aromatase inhibitors for ovulation induction

CONTEXT

For the last 40 yr, the first line of treatment for anovulation in infertile women has been clomiphene citrate (CC). CC is a safe, effective oral agent but is known to have relatively common antiestrogenic endometrial and cervical mucous side effects that could prevent pregnancy in the face of successful ovulation. In addition, there is a significant risk of multiple pregnancy with CC, compared with natural cycles. Because of these problems, we proposed the concept of aromatase inhibition as a new method of ovulation induction that could avoid many of the adverse effects of CC. The objective of this review was to describe the different physiological mechanisms of action for CC and aromatase inhibitors (AIs) and compare studies of efficacy for both agents for ovulation induction.

EVIDENCE ACQUISITION

We conducted a systematic review of all the published studies, both controlled and noncontrolled, comparing CC and AI treatment, either alone or in combination with gonadotropins, for ovulation induction or augmentation, identified through the Entrez-PubMed search engine.

EVIDENCE SYNTHESIS

Because of the recent acceptance of the concept of using AIs for ovulation induction, few controlled studies were identified, and the rest of the studies were pilot or preliminary comparisons. Based on these studies, it appears that AIs are as effective as CC in inducing ovulation, are devoid of any antiestrogenic side effects, result in lower serum estrogen concentrations, and are associated with good pregnancy rates with a lower incidence of multiple pregnancy than CC. When combined with gonadotropins for assisted reproductive technologies, AIs reduce the dose of FSH required for optimal follicle recruitment and improve the response to FSH in poor responders.

CONCLUSIONS

Preliminary evidence suggests that AIs may replace CC in the future because of similar efficacy with a reduced side effect profile. Although worldwide experience with AIs for ovulation induction is increasing, at present, definitive studies in the form of randomized controlled trials comparing CC with AIs are lacking.

Fertility preservation in female cancer patients: current developments and future directions

OBJECTIVE

To review the current advances in fertility preservation strategies and to discuss future directions with an emphasis on ovarian tissue cryobanking.

DESIGN

The publications related to fertility preservation in cancer patients were identified through Medline and other bibliographic databases, focusing on the most recent developments.

CONCLUSION(S)

There are several options for fertility preservation in cancer patients. Even though most of them are still experimental and their efficacy and reliability have not been determined, the future of fertility preservation in women with cancer is promising. In particular, the recent report of a live birth after transplantation of human ovarian tissue has reinforced the clinical potential of ovarian tissue banking for fertility preservation. Many exciting studies are underway to improve the efficacy and solve the problems with current fertility preservation strategies. It is inevitable that we will see the emergence of more complex ethical problems with the application of new technologies to humans. However, continuous efforts to improve current strategies and to develop new strategies will benefit many women and children who are facing premature ovarian failure and sterility.

What can the clinician do to improve implantation?

Implantation is a complicated process that requires the orchestration of a series of events involving both the embryo and the endometrium. Even with the transfer of high quality embryos, implantation rates remain relatively low. The growing tendency towards transferring fewer embryos provides further incentives to improve implantation rates. In this article, the various clinical strategies employed to increase the chance of implantation are reviewed. Embryo transfer technique is a critical step in assisted reproductive technology cycles. Recent studies have shown significant improvements in clinical pregnancy rates resulting from careful embryo transfer technique, appropriate catheter type and placing for embryo transfer. Increasingly, adjuvant pharmaceutical therapies are also being applied with the aim of improving embryo implantation. However, the evidence for their efficacy and safety is limited. Recent evidence suggests that adoption of milder ovarian stimulation regimens may provide a more effective clinical approach to improving implantation, since beneficial effects have been shown for both endometrial receptivity and embryo quality.

Letrozole versus human menopausal gonadotrophin in women undergoing intrauterine insemination

This pilot study was conducted to compare the results of intrauterine insemination (IUI) under ovarian stimulation with either letrozole (Femara) or human menopausal gonadotrophin (HMG). A randomized controlled trial was conducted. Eighty women aged 20-35 years with unexplained infertility of at least 2 years' duration were randomized according to a computer-generated randomization list into the letrozole group and the HMG group. Letrozole was administered at 5 mg/day from day 3 to day 7 of the IUI cycle. HMG injections were started on day 3 at a dose of 75 IU for women under 30 years old and 150 IU for women over 30 years old and monitored periodically by vaginal ultrasound and oestradiol concentrations. The variables selected for analysis were clinical pregnancy rate, endometrial thickness, length of follicular phase and number of preovulatory follicles. No statistically significant difference in clinical pregnancy rates per cycle was found for patients in the letrozole or HMG group (18.4 versus 15.7%). Cost was significantly higher in the HMG stimulation cases (P < 0.001) and no injections were required in the letrozole group. In conclusion, letrozole offers a new treatment regimen in ovarian stimulation regimens for IUI that is cost effective, simple and convenient for the patients.

Therapeutic strategies for ovulation induction in infertile women with polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is a heterogeneous disorder characterized by hirsutism, obesity, hyperandrogenism and insulin resistance. The syndrome is often accompanied by infertility because of anovulation. Many approaches have been proposed to solve this problem, with the most commonly used therapies being ovarian drilling and pharmacological ovulation induction. Ovarian drilling is a procedure in which a laser fiber or electro-surgical needle punctures the ovary four to ten times. Side-effects are rare and often related to surgery itself. Pharmacological strategies include administration of metformin and insulin-sensitizing agents, clomiphene citrate (CC), gonadotropins and aromatase inhibitors. Metformin appears valuable in increasing ovulation rate, menstrual cyclicity and pregnancy rate. CC is an oral estrogen antagonist that raises circulating concentrations of follicle-stimulating hormone (FSH) and induces follicular growth in most women with PCOS and anovulation. Failure to respond is associated with high body mass index and high androgen levels. Aromatase inhibitors mimic the central reduction of negative feedback through which CC works. Ovulation induction with recombinant FSH has proved successful, but treatment requires skill and experience to avoid multiple pregnancies and ovarian hyperstimulation syndrome. The hypothetical deleterious effects of the high luteinizing hormone concentrations observed in PCOS patients seem to be related to the concomitant hyperinsulinemia (and/or insulin resistance). A thorough understanding of the syndrome and a careful assessment of each patient are the mainstays for choosing an appropriate treatment regimen.

The role of aromatase inhibitors in ameliorating deleterious effects of ovarian stimulation on outcome of infertility treatment

Clinical utilization of ovulation stimulation to facilitate the ability of a couple to conceive has not only provided a valuable therapeutic approach, but has also yielded extensive information on the physiology of ovarian follicular recruitment, endometrial receptivity and early embryo competency. One of the consequences of the use of fertility enhancing agents for ovarian stimulation has been the creation of a hyperestrogenic state, which may influence each of these parameters. Use of aromatase inhibitors reduces hyperestrogenism inevitably attained during ovarian stimulation. In addition, the adjunct use of aromatase inhibitors during ovarian stimulation reduces amount of gonadotropins required for optimum stimulation. The unique approach of reducing hyperestrogenism, as well as lowering amount of gonadotropins without affecting the number of mature ovarian follicles is an exciting strategy that could result in improvement in the treatment outcome by ameliorating the deleterious effects of the ovarian stimulation on follicular development, endometrial receptivity, as well as oocyte and embryo quality.