Extended letrozole therapy for ovulation induction in. Aromatase inhibitors, a new option for inducing ovulation. Ais are divided into two categories, steroidal aromatase inhibitors sais, type 1 inhibitors and nonsteroidal aromatase inhibitors type 2 inhibitors that is based on their mechanism of action and structure. Ais exert an ovulationinducing effect by inhibiting the aromatase, and ubiquitous but mostly found in the granulosa cells, fat tissue, and placenta cytochrome p450 enzyme complex. Aromatase inhibitors for ovulation induction and ovarian. Aromatase inhibitors are as effective as or superior to cc in ovulation induction and in superovulation. Aromatase inhibitors ais were introduced 15 years ago as possible oral agents for ovulation induction in polycystic ovary syndrome pcos. The medications were prescribed using an escalating dose if ovulation did not occur. Aromatase inhibitors ais are a novel class of drugs that were introduced for ovulation induction in 2001.
Because of these problems, we proposed aromatase inhibition as a new method of ovulation induction. The role of aromatase inhibitors in ameliorating deleterious effects of ovarian stimulation on outcome of infertility treatment. A void aromatase inhibitors in these situations page 58 why aromatase inhibitors are superior to clomiphene page 60 five pearls for inducing ovulation page 73 the use of aromatase inhibitors for. Use of an aromatase inhibitor for induction of ovulation. Thereafter, many studies discussed the efficacy of aromatase inhibitors in inducing ovulation in different clinical situations 2 6. The safety of letrozole for ovulation induction have been seriously questioned. Use of the aromatase inhibitor letrozole for ovulation induction in women with polycystic ovarian syndrome. Aromatase inhibitors in ovulation induction request pdf. A void aromatase inhibitors in these situations page 58 why aromatase inhibitors are superior to clomiphene page 60 five pearls for inducing ovulation page 73 the use of aromatase inhibitors for induction of ovulation represents an offlabel indication. Letrozole is one of the thirdgeneration aromatase inhibitors used more extensively than others for the treatment of infertility.
Letrozole is an attractive option with its oral route of administration, cost, safety profile and effectiveness in ovulation induction and ovarian. For anovulatory infertility, cc treatment will likely be effective only in conditions in which adequate levels of circulating estrogen exist to exert estrogennegative feedback on gonadotropin production, which in turn could be antagonized by the antiestrogenic effect of cc. Nonsteroidal aromatase inhibitors nsais are one of two categories of aromatase inhibitors ais. Pregnancy outcome after ovulation induction with aromatase.
The ai, letrozole, is effective in ovulation induction in women with pcos resistant to clomifene citrate and ovarian stimulation for intrauterine insemination and in vitro fertilization ivf. For these reasons, aromatase inhibitors can be used for ovulation induction in pcos. Because of these problems, the concept of aromatase inhibition was proposed as a new method of ovulation induction that could avoid many of. Ovulation induction remains a milestone in the treatment of women with anovulatory infertility. Letrozole is one of the thirdgeneration aromatase inhibitors used more extensively than. Letrozole is more effective than clomiphene for ovulation induction in women with pcos and bmi 30. Recent findings in a multicentre, randomized controlled trial comparing letrozole with clomiphene in 750 pcos patients having regular intercourse, live birth rates were. It is, however, being increasingly used as a treatment by fertility specialists to aid the development of ovarian follicles. Thereafter, many studies discussed the efficacy of aromatase inhibitors in inducing ovulation in different clinical situations 26. Ovarian stimulation with the aromatase inhibitor letrozole has been proposed for ovulation induction in order to treat unexplained female infertility.
Approximately 25 percent of female infertility cases stem from problems with ovulation, so ovulation induction can be a beneficial and costeffective first treatment. Aromatase inhibitors for ovulation induction request pdf. Aromatase inhibitors for ovulation induction oxford academic. Aromatase inhibitors are a class of drugs that block estrogen biosynthesis, thereby reducing negative estrogenic feedback at the pituitary. Aromatase inhibitor an overview sciencedirect topics. Aromatase inhibitors are the newest type of fertility drugs used in the infertility treatment of both men and women. The medical team at georgia reproductive specialists has begun incorporating letrozole into treatment plans for appropriately selected patients. Ovulation induction in women with polycystic ovary syndrome. Aromatase inhibitors, infertility, ovulation induction, birth defects, multiple pregnancy, polycystic ovary syndrome pcos.
Recent studies have found that aromatase inhibitors may be safe and useful agents for ovulation induction in patients with polycystic ovarian syndrome as well a treatment option for superovulation in patients with either unexplained infertility or endometriosis. Letrozole versus clomiphene for ovulation induction mdedge. Normogonadotropic anovulation, including polycystic ovary syndrome pcos, is one of the main causes of infertility. Aromatase inhibitors were originally used in the treatment of breast cancer and prostate cancer, but now have proven effective at increasing the chances of getting pregnant. Daya hamilton, ontario, canada infertility is a fairly prevalent disorder that affects one in seven couples in the reproductive age. Ovulation induction ovulation induction at a glance. The use of aromatase inhibitors for ovulation induction and. Clomiphene citrate cc, the oral antiestrogen has long been used as the first line drug for induction of ovulation. The concept of using aromatase inhibitors in place of clomiphene citrate cc for ovulation induction was introduced 10 years ago. Others, as well as ourselves, have reported the success of letrozole, one of the thirdgeneration aromatase inhibitors, in inducing and augmenting ovulation, in addition to other benefits associated with reducing the. Clomiphene isassociatedwithahighovulation 6080%butrelatively poor pregnancy rate 3040%.
Cc leads to long lasting estrogen receptor depletion. A historical perspective of aromatase inhibitors for ovulation induction. Aromatase inhibitors for ovulation induction the journal of clinical. Clearly, an inexpensive yet equally efficacious oral alternative would be ideal.
Aromatase inhibitors have been proposed as an alternative treatment to clomiphene. Use of aromatase inhibitors to induce ovulation has, therefore, been advocated because of their ease of administration, low cost and potential superiority over cc. Polycystic ovary syndrome occurs in 4%8% of women worldwide and usually leads to anovulatory subfertility. We believe aromatase inhibitors are acceptable alternatives to cc as first line oral agents for ovulation induction or controlled ovarian stimulation. To evaluate evidence for use of aromatase inhibitors for ovulation induction and pregnancy in patients with polycystic ovary syndrome pcos. Many studies have recently shown that using letrozole for ovulation induction results in better rates of successful ovulation and has no adverse. The two main indications for cc treatment are induction of ovulation in anovulatory infertility and stimulating multifollicular ovulation or enhancing ovulation in ovulatory infertile women, e.
Recently, the safety of letrozole for ovulation induction have been seriously questioned. Letrozole is an attractive option with its oral route of administration, cost, safety profile and. Aromatase inhibitors such as testolactone have been approved for the treatment of gynecomastia in children and adolescents. Aromatase inhibitors may be an effective alternative treatment to clomiphene citrate for both ovulation induction and superovulation.
Aromatase inhibitors have been introduced as a new treatment modality that could challenge clomiphene citrate as an ovulation induction regiment in patients with pcos. Use of the aromatase inhibitor letrozole for ovulation. Aromatase inhibitors are approved solely for the pallia tive or adjuvant treatment of postmenopausal women with estrogenreceptorpositive breast cancer. Co the use of aromatase inhibitors for ovulation induction. The use of aromatase inhibitors in infertility and gynecology. We believed it was time to develop a more effective ovulation induction agent, and we have demonstrated that aromatase inhibitors ais seem to be a promising alternative to cc for ovulation induction. It has been used offlabel for ovulation induction as part of the ivf process since 2001. During the past decade, aromatase inhibitors have been explored as an option for ovulation induction in women who fail to conceive with. Aromatase inhibitors are promising new drugs for the induction of ovulation and superovulation. Jun 21, 2011 aromatase inhibitors have been introduced as a new treatment modality that could challenge clomiphene citrate as an ovulation induction regiment in patients with pcos. During the past decade, aromatase inhibitors have been explored as an option for ovulation induction in women who fail to conceive with clomiphene citrate. The new third generation aromatase inhibitors are extremely potent and specific oral inhibitors of estrogen production.
Nsais are mainly used to treat breast cancer in women. Pdf aromatase inhibitors for ovulation induction researchgate. It affects about 4% to 8% of women worldwide and often leads to anovulatory subfertility. Aromatase inhibitors for subfertile women with polycystic. Others, as well as ourselves, have reported the success of letrozole, one of the thirdgeneration aromatase inhibitors, in inducing and augmenting ovulation, in addition to.
Letrozole versus clomiphene for ovulation induction. Ovulation induction in women with polycystic ovary. Given the advantages of aromatase inhibitors, they can be used to replace cc as ovulationinducing drugs. In addition, new data suggest that cc may result in cardiac anomalies and other birth defects and in low birth weight babies. Approximately 15% of the infertile population faces an ovulatory disorder. Pdf aromatase inhibitors for ovulation induction mohamed. Letrozole, a thirdgeneration aromatase inhibitor, is the most commonly used for ovulation induction protocols 6,7 and has been integrated into clinical practice to varying degrees. Slideshare uses cookies to improve functionality and performance, and to provide you with relevant advertising. Sep 12, 2012 supported in part by grants from the canadian institutes of health research, ottawa, ontario, canada. Aromatase inhibitors for female infertility reproductive biomedicine. Citrate cc therapy as the discrepancy between ovulation.
If you continue browsing the site, you agree to the use of cookies on this website. Aromatase inhibitors for ovulation induction the journal. Letrozole is an attractive option with its oral route of administration, cost, safety profile and effectiveness in ovulation induction and ovarian stimulation. Aromatase inhibitors for ovulation and pregnancy in. They are effective in inducing ovulation on the basis of the published reports. Use of an aromatase inhibitor for induction of ovulation in patients with an inadequate response to clomiphene citrate.
The prime and only licensed use of letrozole is as an additional adjuvant treatment of breast cancer in postmenopausal women. In a metaanalysis summarizing clinical trials testing aromatase inhibitors used alone or with other medical therapies for ovulation induction in pcos patients, live. Ovulation induction is a treatment for anovulation irregular ovulation, an infertility condition in which follicles in a womans ovary do not mature and release eggs ovulate. In a metaanalysis summarizing clinical trials testing aromatase inhibitors used alone or with other medical therapies for ovulation induction in pcos patients, live birth rates were again significantly higher when letrozole was compared with clomiphene citrate odds ratio or 1.
Ovulation occurred in nine patients 75% and pregnancy occurred in three 25% 1. Potential of aromatase inhibitors for ovulation and. A historical perspective of aromatase inhibitors for. Aromatase inhibitor shows promise in fertility treatment. We reported the success of using aromatase inhibitors for induction of ovulation in world health organization who type ii anovulatory patients. Aromatase inhibitors were introduced in 2001 for induction of ovulation. Recent research has focused on the successful use of aromatase inhibitors, mainly letrozole, for ovulation induction. Letrozole for ovulation induction british fertility society. Use of an aromatase inhibitor for induction of ovulation in. Aromatase inhibitors for ovulation induction the journal of.
Unlike cc, they do not carry an antiestrogenic effect on the endometrium. Since 2005, there have been well over 100 publications describing the use of aromatase inhibitors, predominantly letrozole, in assisted reproduction, including ovulation induction in pcos, combined with gonadotropins in controlled ovarian stimulation for intrauterine insemination or in vitro fertilization, or in women with breast cancer. Their use does not seem to be associated with adverse endometrial. Aromatase inhibitors in stimulated ivf cycles reproductive. Drs mitwally and casper have patent applications for use of aromatase inhibitors for ovulation induction and a licensing agreement with serono for commercialisation of aromatase inhibitors for ovulation induction. Advantages of aromatase inhibitors in ovulation induction relatively short halflife 45 hrs it t t lf db k h iintact central feedback mechanisms increase follicular sensitivity to fsh no adverse effects on endometrium or cervical mucouscervical mucous safe for community gynaecologists. Aromatase inhibitors ais were introduced 15 years ago as possible oral agents for ovulation induction in polycystic ovary syndrome pcos patients. Although several randomized trials have been conducted regarding their use as ovulation induction agents, only few trials are available regarding their efficacy in ivf stimulated cycles. Letrozole belongs to a class of drugs called aromatase inhibitors.