Some women may need medication to help them ovulate the egg during the mid-cycle of menstruation. The process of using medication for ovulation we call ovulation induction. The main reasons for using medication for ovulation are that women have anovulation (no ovulation) or they ovulate irregularly. The second reason is that they ovulate spontaneously but still cannot become pregnant. The medication might help to release more than one egg, which can improve the chances of natural conception.
There are several kinds of oral medication that we use for ovulation induction. Clomiphene citrate (CC) and letrozole are the two most common.
How do we use medication for ovulation induction?
The patient needs to wait for the start of her period. Usually we start oral medication on the second to the firth day of the period for five days. The doctor will adjust the dose of medication that is right for each patient. We usually wait after the last tablet for seven days then it is time of natural ovulation and time of natural conception.
Are there any risks in taking medication for ovulation induction?
The most common risk is twin pregnancy. The chance of twins is usually at 5–8% with clomiphene citrate. The chance of triplets or higher order multiple pregnancy is less than 1%. Some patients may experience nausea and vomiting but this is rare for oral medication. Ovarian cysts may occur with CC, which are more common than with letrozole, but these will spontaneously disappear within 1–3 months and it is rare for them to require specific treatment. The medication is associated with ovarian cancer in the future. There is no known increase in birth defects in women who have taken these medications for ovulation induction.
Is there any monitoring required after taking medication?
Monitoring is not usually required after taking the medication. We use transvaginal ultrasound to measure the egg to make sure that the patient is receiving the right dose to produce a mature egg only for the first or second medication cycles. The patient can also use a home ovulation kit to check the best time of ovulation.
How effective are these medications for ovulation induction in helping women to become pregnant?
The success of these medications depends on many factors. In women not already ovulating, almost 80% who use CC or letrozole over several months will ovulate. Some women will need increasing doses of the medication. Pregnancy rates depend on your age and the length and cause of infertility. These medications are generally more effective in women who do not ovulate regularly. In women who already ovulate, pregnancy rates tend to be lower, especially if the medications are not combined with other treatment such as insemination.