Clomiphene citrate versus letrozole for ovarian stimulation: a pilot study

Effectiveness of cetrorelix for the prevention of premature luteinizing hormone surge during controlled ovarian stimulation using letrozole and gonadotropins: a randomized trial

OBJECTIVE

To evaluate the effectiveness of a GnRH antagonist in preventing premature LH surge under a letrozole and gonadotropin protocol.

DESIGN

Prospective, randomized clinical trial.

SETTING

A teaching hospital and tertiary medical center.

PATIENT(S)

Sixty-one patients were randomly assigned into two letrozole and gonadotropin-treated groups. These were distinguished by the absence (group I) or presence (group II) of supplementation with 0.25 mg of cetrorelix.

INTERVENTION(S)

Controlled ovarian stimulation with letrozole and gonadotropins, cetrorelix and intrauterine insemination.

MAIN OUTCOME MEASURE(S)

Rate of premature LH surge.

RESULT(S)

Compared with group I, the rate of premature LH surge was statistically significantly lower for group II (43.4% [13/30] vs. 19.4% [6/31]), but the amount of gonadotropins used was statistically significantly higher (817.5 +/- 28.5 vs. 907.5 +/- 27.3 IU). Patients with premature LH surge had a statistically significantly lower pregnancy rate (21.4% [9/42] vs. 0 [0/18]) relative to their unaffected counterparts.

CONCLUSION(S)

A flexible protocol of 0.25 mg of cetrorelix for IUI cycles appears to suppress the rate of premature LH surge during ovarian stimulation with letrozole and gonadotropins. However, the incidence of premature LH surge remains too high, and modification will be necessary before the application of cetrorelix to IVF treatment.

Fertility preservation in gynecologic cancers

PURPOSE OF REVIEW

This review focuses on the current options for fertility preservation in young women facing the risk of premature ovarian failure and infertility as a sequel to the treatment of gynecologic cancer.

RECENT FINDINGS

There is a wide range of options to preserve fertility. Embryo freezing is the most established method and the success rate of in-vitro fertilization using frozen-thawed embryos now approaches that of using fresh embryos. Success rates with oocyte cryopreservation are on the rise and begin to approach that of embryo freezing. Exposure to high levels of estrogen during ovarian stimulation can be minimized by utilizing aromatase inhibitors in women with estrogen-sensitive cancers undergoing embryo or oocyte cryopreservation. Ovarian-tissue cryopreservation is used to preserve fertility in children and in patients with time restraints; however, the number of reported cases is very small. Likewise, in-vitro maturation and xenografting are experimental and their potential to preserve fertility remains to be determined.

SUMMARY

A number of fertility-preservation techniques have been developed and many others are in the experimental stages. Consistent with recent ASCO clinical guidelines, all young individuals with gynecologic cancer should be counseled about the available fertility preservation techniques.

Polycystic ovary syndrome

Polycystic ovary syndrome is a heterogeneous endocrine disorder that affects about one in 15 women worldwide. The major endocrine disruption is excessive androgen secretion or activity, and a large proportion of women also have abnormal insulin activity. Many body systems are affected in polycystic ovary syndrome, resulting in several health complications, including menstrual dysfunction, infertility, hirsutism, acne, obesity, and metabolic syndrome. Women with this disorder have an established increased risk of developing type 2 diabetes and a still debated increased risk of cardiovascular disease. The diagnostic traits of polycystic ovary syndrome are hyperandrogenism, chronic anovulation, and polycystic ovaries, after exclusion of other conditions that cause these same features. A conclusive definition of the disorder and the importance of the three diagnostic criteria relative to each other remain controversial. The cause of polycystic ovary syndrome is unknown, but studies suggest a strong genetic component that is affected by gestational environment, lifestyle factors, or both.

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.

A randomized comparison of ovulation induction and hormone profile between the aromatase inhibitor anastrozole and clomiphene citrate in women with infertility

BACKGROUND

IN the present study we evaluated and compared the effects of ovulation and hormonal dynamics induced by anastrozole and clomiphene citrate in women with infertility.

MATERIALS AND METHODS

Thirty-three infertile patients, aged 25-41 years, were enrolled. Patients received either anastrozole 1 mg daily (AI group) or clomiphene citrate 100 mg daily (CC group) from cycle day 3 to day 7. Number of mature follicles (> or =18 mm), endometrial thickness, pregnancy rate and serial hormone profiles (follicle-stimulating hormone (FSH), luteinizing hormone (LH), estradiol (E(2)), testosterone and progesterone) were measured on cycle day 3, day 8, day 10, the day of intrauterine insemination (IUI), day 7 after IUI and day 14 after IUI.

RESULTS

Baseline parameters were similar in the two groups, including age, body mass index, infertility duration and day-3 serum hormones except FSH. The mean FSH value on day 3 was significantly different (4.3 mIU/ml in the AI group vs. 6.3 mIU/ml in the CC group; p < 0.05). The women receiving anastrozole had fewer ovulatory follicles (1.2 in the AI group vs. 1.8 in the CC group; p < 0.05) and a thicker endometrium (10.6 mm in the AI group vs. 7.8 mm in the CC group; p < 0.05). The levels of progesterone and testosterone were similar during ovulation stimulation cycles in both groups. On the other hand, the AI group had a significantly higher LH level but a significantly lower E(2) level in the stimulation cycle.

CONCLUSION

Anastrozole has a high pregnancy rate, although it induces fewer ovulatory follicles compared with clomiphene citrate. The two drugs gave different responses of FSH, LH and E2 during stimulation cycles.

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.

Ovulation induction in normogonadotropic anovulation (PCOS)

Treatment of normogonadotropic anovulatory infertility (World Health Organization class 2, or WHO2) is by induction of ovulation using clomiphene citrate (CC), followed by follicle-stimulating hormone (FSH) in cases of treatment failure. Not all patients will become ovulatory or will conceive with this treatment. Others, exhibiting multifollicular instead of monofollicular development, may encounter complications such as ovarian hyperstimulation and multiple pregnancy. Recently introduced alternative treatment interventions-such as insulin-sensitizing drugs, aromatase inhibitors, or laparoscopic electrocautery of the ovaries-may offer the possibility of improving the efficacy of the classical ovulation induction algorithm. Based on initial patient characteristics, it may be possible to identify specific patient subgroups with altered chances of success or complications while using one of these interventions. Regarding CC and FSH ovulation induction, this has been performed using multivariate prediction models. This approach may enable us to improve safety, cost-effectiveness, and patient convenience in future ovulation induction.

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.

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.

Successful treatment of an aggressive recurrent post-menopausal endometriosis with an aromatase inhibitor

The current case report describes the development and medical treatment of an aggressive pelvic endometrioma in a post-menopausal patient, who had undergone abdominal hysterectomy and salpingo-oophorectomy a decade earlier. The patient was referred to the authors' centre because of right-sided sciatic pain. Three months before her admission she was hospitalized elsewhere due to subacute bowel obstruction. She was operated on and a resection of a part of sigmoid colon and an endometrioma, which was the cause of the subobstruction, was carried out. During the clinical investigation for the right-sided sciatic pain, an intrapelvic mass was found, which was compressing the lumbo-sacral plexus mimicking sciatica. The diagnosis of recurrent endometrioma was confirmed by a computerized tomography-guided biopsy and the decision was made to treat it with an aromatase inhibitor (letrozole). Eighteen months later, the endometrioma was almost completely regressed and the patient was free of symptoms. Medical management of recurrent post-menopausal endometriosis with aromatase inhibitors seems to be an effective alternative treatment to surgery.

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.

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.

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.

Patient-tailored conventional ovulation induction algorithms in anovulatory infertility

Conventional treatment of normogonadotropic anovulatory infertility is ovulation induction using the antiestrogen clomiphene citrate, followed by follicle-stimulating hormone. Multiple follicle development, associated with ovarian hyperstimulation, and multiple pregnancy remain the major complications. Cumulative singleton and multiple pregnancy rate data after different induction treatments are needed. Newer ovulation induction interventions, such as insulin-sensitizing drugs, aromatase inhibitors and laparoscopic ovarian electrocoagulation, should be compared with conventional strategies. Ovulation induction efficiency might improve if patient subgroups with altered chances for success or complications with new or conventional techniques could be identified, using multivariate prediction models based on initial screening characteristics. This would make ovulation induction more cost-effective, safe and convenient, enabling doctors to advise patients on the most effective and patient-tailored treatment strategy.

Emerging drugs in assisted reproduction

Infertility affects approximately 15% of couples of reproductive age. In assisted reproductive technology (ART), medications play a crucial role in stimulating ovaries to produce several oocytes and prepare the endometrium to be receptive after replacing one or more embryos into the uterine cavity. The availability of recombinant human follicle stimulating hormone, luteinising hormone and human chorionic gonadotrophin; of gonadotrophin-releasing hormone (GnRH) agonists and antagonists; and of luteal supplementation with progesterone have allowed the tailoring of several stimulation schemes, which have enhanced the pregnancy outcome after ART treatment. However, the remaining risk of ovarian hyperstimulation syndrome, the still low implantation rates, the unacceptably high rates of multiple pregnancies and the daily parenteral administration of medications do not constitute the features of a patient-friendly procedure. Therefore, a number of molecules with gonadotrophin-like activity, inhibition of GnRH receptor ability, or endometrium receptivity enhancement properties are currently under active investigation. Orally bioactive therapeutic preparations, in particular, may revolutionize in vitro fertilisation (IVF) treatment in the near future. Nevertheless, the implementation of mild ovarian stimulation protocols with single embryo transfer policy and further development of oocyte in vitro maturation techniques may lead to a less drug orientated IVF treatment.

Clomiphene citrate--end of an era? A mini-review

The purpose of this review is to examine whether the time has come to replace clomiphene citrate (CC) as the first line therapy for WHO group II (eu-oestrogenic) infertility, the majority of which is associated with polycystic ovary syndrome. CC has been the first line therapy for these cases for the last 40 years. It is a simple, cheap treatment, almost devoid of side effects which yields a single live birth rate of approximately 25% of starters. Non-response to CC and the gap between ovulation and pregnancy rates have variously been attributed to its anti-estrogen effects, and high LH and androgen concentrations. Three possible contenders for the replacement of CC as first-line treatment are scrutinized: metformin, aromatase inhibitors and low-dose FSH. Each has their advantages and disadvantages, but none of them, while showing much potential promise, has been proven, as yet, to be a feasible replacement for CC in this role. For CC, it may not yet be the end of an era but it may be the beginning of the end.

Management of Infertility in Women with Polycystic Ovary Syndrome

The management of infertility in women with polycystic ovary syndrome (PCOS) centers around options for inducing ovulation. This is an evidence-based review of the management of PCOS, which includes a MEDLINE search of publications between 1986 and May 2005 and a search of the Cochrane Database. Weight loss, exercise, and metformin will induce ovulation in many insulin-resistant women and obese women with PCOS, and should always be the first-line treatment. Ovulation induction has been performed with clomiphene citrate (clomifene) as the first-line treatment, but the use of aromatase inhibitors has been shown to be as successful. The strategies for reducing the risks of gonadotropin therapy such as low-dose follicle-stimulating hormone (FSH) stimulation and the addition of metformin are discussed. Both gonadotropin releasing-hormone agonists and antagonists are equally effective in in vitro fertilization stimulation in conjunction with FSH therapy. Metformin may have a benefit in pregnancy in reducing the risks of miscarriage and diabetes mellitus; however, prospective trials are still lacking.

Is ovulation induction still a therapeutic problem in patients with polycystic ovary syndrome?

Polycystic ovary syndrome (PCOS) is one of the most common endocrine diseases affecting women of fertile age, and is characterized by hyperandrogenism, chronic anovulatory cycles and oligomenorrhea or amenorrhea. Given the repercussions of chronic anovulation on sterility, PCOS is a heavy social burden. Here we describe the procedures used to induce ovulation in PCOS patients, the surgical approach and medical treatments that are still being experimented.