Ovulation induction using sequential letrozole/gonadotrophin in infertile women with PCOS: a randomized controlled trial

Letrozole replaces clomiphene as first-line for PCOS ovulation induction

Metabolic optimization + letrozole -> clomiphene -> OWR

Ovulation induction in women with infertility: a new indication for aromatase inhibitors

Bulun SE, 2003 · Fertil Steril ·

The third-generation aromatase inhibitors were initially introduced to treat postmenopausal breast cancer. We now realize that many other potential indications for aromatase inhibitors exist, especially in the field of gynecology. Preliminary data were suggestive that aromatase inhibitors could be used to treat endometriosis and uterine leiomyomata and induce or augment ovulation. Aromatase inhibitors promote ovulation, most likely by increasing endogenous FSH production owing to decreased estrogen biosynthesis in the ovary and extraovarian tissues, including the brain. Aromatase inhibitors differ from the estrogen antagonist clomiphene citrate in that they do not exert a direct unfavorable effect on endometrial growth and development during the menstrual cycle. Healey et al. (1) report important findings on the effects of the addition of an aromatase inhibitor to gonadotropin injections for superovulation. A relatively large number of patients and a control group were studied, and several clinically useful outcomes including pregnancy rates were reported. The addition of letrozole to an ovulation induction regimen using injectable gonadotropins in a mixed population of patients with infertility does not seem to offer any benefits over gonadotropin-only cycles, because the decreased gonadotropin dose (the only apparent benefit) was offset by increased complexity of the treatment. Further randomized clinical trials using a similar design and patient sample may not provide clinically useful data. On the other hand, optimization of this regimen (gonadotropin plus aromatase inhibitor) in poor responders may offer an alternative in this subset of women (2). From the existing literature, it appears that use of an aromatase inhibitor alone to induce or augment ovulation will continue to be an exciting area of research future (3, 4). In particular, the dosing and timing of administration (late luteal versus early follicular) of an aromatase inhibitor for ovulation induction should be optimized. Defining the hormonal profiles of the women who will benefit the most from aromatase inhibition may further increase the success of treatment. In summary, Healey et al. (1) should be congratulated for conducting this interesting work. Carefully designed randomized studies on the use of aromatase inhibitors for ovulation induction or augmentation are warranted.

A brief update on the evidence supporting the treatment of infertility in polycystic ovary syndrome

Costello MF et al., 2019 · Aust N Z J Obstet Gynaecol ·

Polycystic ovary syndrome (PCOS) is complex with reproductive, metabolic and psychological features. Infertility is a prevalent presenting feature of PCOS with approximately 75% of these women suffering infertility due to anovulation, making PCOS by far the most common cause of anovulatory infertility. Previous guidelines either lacked rigorous evidence-based processes, did not engage consumer and international multidisciplinary perspectives, or were outdated. This review paper aims to provide a brief update on the best available and most current research evidence supporting the treatment of PCOS which informed the recommendations in the assessment and treatment of infertility section of the international evidence-based guideline on PCOS 2018. International evidence-based guideline development engaged professional societies and consumer organisations with multidisciplinary experts and women with PCOS directly involved at all stages. Lifestyle change alone is considered the first-line treatment for the management of infertile anovulatory PCOS women who are overweight or obese. Letrozole should now be considered first-line pharmacological treatment for ovulation induction to improve fertility outcomes. Clomiphene citrate alone and metformin alone could also be used as first-line pharmacological therapy, although both are less effective than letrozole and metformin is less effective than clomiphene citrate in obese women. Gonadotrophins or laparoscopic ovarian surgery are usually second-line ovulation induction therapies. In the absence of an absolute indication for in vitro fertilisation (IVF) / intracytoplasmic sperm injection, women with PCOS and anovulatory infertility could be offered IVF as third-line therapy where firstor second-line ovulation induction therapies have failed. This review provides the best available evidence informing recommendations (along with clinical expertise and consumer preference) which provide clinicians with clear advice on best practice for the management of infertile women with PCOS.

Aromatase inhibitors in ovulation induction

Mitwally MF et al., 2004 · Semin Reprod Med ·

The new third generation aromatase inhibitors are extremely potent and specific oral inhibitors of estrogen production. We reported the success of using aromatase inhibitors for induction of ovulation in World Health Organization (WHO) type II anovulatory patients. Promising pregnancy rates were associated with the use of aromatase inhibitors for induction of ovulation in these women. In addition, the use of aromatase inhibition in conjunction with gonadotropin injection was associated with a significant reduction in the gonadotropin dose required for optimum controlled ovarian hyperstimulation. We believe that these oral agents are efficient and safe and have many advantages compared with clomiphene citrate (CC). We propose that aromatase inhibitors will replace CC in the future as the new primary treatment for ovulation induction. In this review, we present an update on the use of aromatase inhibitors for induction of ovulation and we discuss several new areas of potential interest regarding the use of aromatase inhibitors, either alone or together with recombinant follicle-stimulating hormone (FSH) for infertility treatment. Further research in these areas may demonstrate an expanded role in assisted reproductive technologies.