What is Letrozole?

Letrozole is an oral medication that induces ovulation by blocking the conversion of testosterone into estrogen. This will, in effect, increase the brain production of FSH and LH and send a message to the ovary to increase the growth of the follicles (eggs). Letrozole medication is often used to increase the ovulation rate or improve ovulation in women who are already ovulating.  It was found to be superior to Clomid when inducing ovulation in patients with polycystic ovarian syndrome. Unlike Clomid, Letrozole does not come with the side effects of thinning the uterine lining or decreasing the cervical mucous. Most women experience no side effects. The pregnancy rates are typically 20-25%.


The injectable medications known as Gonal-F and Follistim are synthetic forms of follicle stimulating hormones. Menapur is a combination of follicle stimulating hormone and luteinizing hormone.  The key benefit of these injections is that they directly stimulate the growth of the follicle (egg), increasing the estrogen levels and the number of follicles growing.  Gonadotropins can also be used in combination with Clomid or Letrozole to minimize the dosage of gonadotropins and decrease the risk of multiple births.