New advances in ovulation induction.

PURPOSE OF REVIEW: To review recent advances in ovulation induction.

RECENT FINDINGS: Aromatase inhibitors can replace clomiphene citrate as ovulation-inducing substances. The most widely used aromatase inhibitor for this purpose is letrozole and the optimal dose is 5 mg daily for 5 days. Compared to clomiphene citrate, it is associated with a thicker endometrium and a better pregnancy rate. It is as effective as gonadotropin but yet less expensive. The overall rates of congenital malformation among newborns conceived after infertility treatment with letrozole or clomiphene citrate are similar. When letrozole is combined with gonadotropin, it leads to lower gonadotropin requirements with pregnancy rates comparable to gonadotropin treatment alone. Another promising aromatase inhibitor is anastrazole. Recent evidence suggests that luteinizing hormone activity in human menopausal gonadotropin modifies follicular development so that fewer intermediate-sized follicles develop. Compared to the use of follicular stimulating hormone only, human menopausal gonadotropin is associated with less ovarian hyperstimulation.

SUMMARY: Aromatase inhibitors are alternative drugs to clomiphene or gonadotropin for ovulation induction or superovulation.