insulin sensitizing agents can increase ovulation rates in some women with PCOS. Metformin has been used widely for that purpose.
Aromatase Inhibitors
Anastrozole and letrozole are triazole derivatives that act as potent, competitive, nonsteroidal inhibitors of aromatase. Aromatase is an enzyme which catalyzes the rate-limiting step in estrogen production. Letrozole inhibits estrogen production in the hypothalamus–pituitary axis, which results in compensatory increase in gonadotropin-releasing hormone (GnRH) and FSH and stimulates ovarian follicular development. The advantage of letrozole is that it avoids peripheral antiestrogenic effects on the endometrium while stimulating monofollicular growth.9 Letrozole (2.5–5 mg daily) or anastrozole (1 mg daily) is administered for 5 days and may be accompanied by FSH (at the normal doses for PCOS patients) and human chorionic gonadotropin (hCG; 10,000 IU) when the follicle diameter reaches 18 …show more content…
Ovarian hyperstimulation, higher risks of multiple pregnancy, and the expence and frustration associated with cancelled cycles usually can be avoided by using a “low-slow” treatment regimen involving low doses (37.5-75 IU daily), small increments, and a longer duration of stimulation. HCG is administered to trigger ovum release, it leads to maturation of the oocyte, rupture of the follicle, and formation of the corpus luteum. The step-down regimen starts with the maximum recommended dose (150-225 IU daily), which is reduced gradually in order to promote continued development of only the more sensitive dominant follicle. Insulin resistant women may be less sensitive to gonadotropin stimulation. In such women, metformin treatment before and during gonadotropin stimulation can help to improve response, limit the number of smaller developing follicles13 and reduce the likelihood of cycle cancellation for excessive
Aromatase Inhibitors
Anastrozole and letrozole are triazole derivatives that act as potent, competitive, nonsteroidal inhibitors of aromatase. Aromatase is an enzyme which catalyzes the rate-limiting step in estrogen production. Letrozole inhibits estrogen production in the hypothalamus–pituitary axis, which results in compensatory increase in gonadotropin-releasing hormone (GnRH) and FSH and stimulates ovarian follicular development. The advantage of letrozole is that it avoids peripheral antiestrogenic effects on the endometrium while stimulating monofollicular growth.9 Letrozole (2.5–5 mg daily) or anastrozole (1 mg daily) is administered for 5 days and may be accompanied by FSH (at the normal doses for PCOS patients) and human chorionic gonadotropin (hCG; 10,000 IU) when the follicle diameter reaches 18 …show more content…
Ovarian hyperstimulation, higher risks of multiple pregnancy, and the expence and frustration associated with cancelled cycles usually can be avoided by using a “low-slow” treatment regimen involving low doses (37.5-75 IU daily), small increments, and a longer duration of stimulation. HCG is administered to trigger ovum release, it leads to maturation of the oocyte, rupture of the follicle, and formation of the corpus luteum. The step-down regimen starts with the maximum recommended dose (150-225 IU daily), which is reduced gradually in order to promote continued development of only the more sensitive dominant follicle. Insulin resistant women may be less sensitive to gonadotropin stimulation. In such women, metformin treatment before and during gonadotropin stimulation can help to improve response, limit the number of smaller developing follicles13 and reduce the likelihood of cycle cancellation for excessive