Mild Stimulation for IVF

In mild stimulation of ovulation, clomiphene or letrozole pills are taken for five days, usually starting at day 3 of the cycle, although the treatment could be started sooner or later than day 3. This is decided by the doctor, depending on a woman's cycle length and her ovarian reserve. Gonadotropin injections follow clomiphene or letrozole pills until the follicle grows to 17-20 mm, usually taking 2-4 days. During the stimulation, one or two follicle monitoring ultrasounds should be done. Sometimes, antagonist injections are used in order to prevent ovulating ahead of time. However, this significantly increases the costs of the protocol.

Advantages of mild stimulation include using less medication, greater cost-effectiveness, lesser patient discomfort, and the risk of developing ovarian hyperstimulation syndrome are minimal. We expect to get 2-7 eggs from aspiration using mild stimulation, and there are usually no extra embryos for cryopreservation. Pregnancy rates using this method can be compared to standard stimulation, but since there is no cryopreservation, the cumulative success rate is lower.

Patients who benefit from mild stimulation protocols are patients with high ovarian reserve. Mild stimulation protocols in such patients lower the chance of ovarian hyperstimulation syndrome, otherwise very high. Also, because of their high ovarian reserve, they may produce a more significant number of eggs in mild stimulation protocols; therefore, they may have cryopreserved embryos as well.