Who it is for
Ovarian stimulation is first of all for women who do not ovulate, or ovulate poorly: long and irregular cycles, absent periods, polycystic ovary syndrome. It is also offered as a first step in unexplained infertility, when both work-ups are normal and nothing accounts for the wait.
It is pointless if the tubes are blocked or the sperm severely abnormal: the egg will be there, and meet nothing. That is why no clinic stimulates before checking tubal patency and a semen analysis.
How it works
- By mouth: clomifene citrate or letrozole, five days early in the cycle. Letrozole has become first choice in polycystic ovary syndrome: more ovulations and births than clomifene, with a similar rate of multiple pregnancies.
- By injection: low-dose gonadotrophins, daily, subcutaneously. The dose starts low and rises slowly — this step-up protocol is what prevents ten follicles growing instead of one.
Monitoring is the heart of the treatment: two to four scans to count and measure follicles, sometimes with an oestradiol level. Once a follicle reaches 17–18 mm, a trigger injection brings ovulation about thirty-six hours later, and intercourse is timed to that window.
What it achieves
Stimulation adds a few percentage points to the pregnancy rate per cycle. That is modest, and expected: it corrects one factor only. For a woman who was not ovulating at all, the gain is enormous, since the probability moves from zero to ordinary.
It is not continued indefinitely. Beyond six ovulatory cycles without pregnancy, carrying on adds nothing: it is time to change technique.
Risks, and the rule that avoids them
The main risk is multiple pregnancy. If three or more follicles develop, the cycle must be cancelled — no trigger, and contraception until the period. That is frustrating after ten days of injections, and it is still the right call: a triplet pregnancy is not a success, it is a complication.
Ovarian hyperstimulation syndrome can occur at this stage but stays rare at low doses. Hot flushes, mood swings, pelvic heaviness and functional cysts are common and resolve with the cycle.
What is rarely mentioned
Timed intercourse has a cost no protocol measures: sex becomes an appointment. Many couples describe lower desire, and sometimes erectile difficulty on the day, in men who had never experienced it. It is not abnormal, and it can be planned around — shifting a day, or several acts across the window rather than one at the appointed hour.