It is important when a drug is first used that the ovarian response is monitored to ensure it is appropriate and importantly, that it is not excessive. An excessive response that induces too many follicles to develop and leads to too many eggs being released is risky as it could lead to multiple pregnancies like triplets and quadruplets that pose risks of prematurity to the babies.
During treatment with oral agents such as letrozole and clomiphene, it is advisable that monitoring be performed for at least the first one or two cycles. This will not only check that a response is occurring, it will also confirm that it is not excessive. Monitoring is achieved using transvaginal ultrasound scanning to monitor follicle development. Scanning is usually combined with blood tests for measuring hormone levels that will enable the timing of ovulation, and of the right time for sexual intercourse, to be calculated. A blood test for progesterone levels can confirm whether ovulation occurred, but because it is performed around 1 week after ovulation, serum progesterone levels cannot be used to advise on timing of intercourse.
When using FSH injections for inducing ovulation, ultrasound scan monitoring is always required.
In cases of treatment for hyperprolactinaemia (usually with drugs), prolactin levels in the blood are monitored to ensure that they are returning to the normal range. As prolactin levels normalise, patients will find that their menstrual cycles are becoming more regular, which would be an indication that ovulation has resumed.