Letrozole is used frequently as an infertility treatment. It is a recent addition to the drugs that are currently used for fertility treatment. This medication is a helpful aid to induce an egg to develop and be released in women who are not ovulating naturally; this is known as ovulation induction. Fertility drugs can also be utilized to increase the probability of pregnancy in women who are already ovulating.
Clomiphene Citrate or Serophene has been the drug of first choice for both ovulation induction or superovulation for several years. By and large, it has been a relatively effective medication. Clomid is known to last longer in the body and so may have an adverse effect on the cervical mucus and uterine lining.
Pregnancy rates with letrozole are similar to those seen with clomiphene citrate and are lower than the pregnancy rates seen with gonadotropins. Older patients will have a reduced chance of success than younger patients.
Treatment with letrozole may still be successful even if other treatments have failed. Some data has shown that in women who did not ovulate with clomiphene citrate, may ovulate with letrozole.
Letrozole has also been shown to improve outcome in cycles combining injectable FSH with oral ovulation induction. Recent studies report that the combination of letrozole and FSH enhances follicular recruitment while reducing the amount of FSH needed for optimal stimulation, thus reducing the cost of the cycle. This method has also been useful in patients who previously responded poorly to superovulation treatment protocols.
Letrozole works by reducing estrogen levels. Low estrogen levels may cause a woman to have symptoms. The data on side effects is from women who have been utilizing letrozole for an extended period of time as a means of treating breast cancer. The treatment duration for letrozole is only five days. In our practice, we have seen side effects that are comparable to those seen with clomiphene citrate:
- Hot flashes
- Breast tenderness