Ovulation induction involves taking oral fertility medication to stimulate ovulation in women who are not ovulating normally (these are usually women with irregular or infrequent menstruations).
Medications used for ovulation induction include:
Clomiphene is a pill that is taken orally for five days at the beginning of a menstrual cycle. It is a SERM (selective estrogen receptor modulator) and works by blocking the effect of estrogen on the brain. The brain responds by producing more of its own gonadotropin hormones to stimulate the ovary to produce eggs. For women who do not ovulate naturally, Clomiphene has been shown to induce ovulation in approximately 60% of women. Clomiphene can have the side effect of blocking estrogen receptors in the endometrium and cervix. This may limit the number of cycles that you can take consecutively. There is an increased risk of multiple pregnancy, estimated at 8-10%.
Letrozole is a pill that is taken orally for five days at the beginning of a menstrual cycle. It is an Aromatase Inhibitor and works by lowering estrogen levels. The brain responds in a similar way as Clomiphene and produces more gonadotropin hormone. It has recently been shown to be an excellent option for women with Polycystic Ovarian Syndrome. It has a lower risk of multiple pregnancy (4%) compared to Clomiphene.