Excessive stimulation of ovaries is called ovarian hyperstimulation. Ovarian hyperstimulation occurs in a small percentage of patients when too many follicles develop in the ovary. The ovary then grows to a large size and leaks fluid, resulting in nausea and bloating, dehydration, and, if severe, fluid collection around the abdominal organs, or ascites. In very severe cases, fluid collects around other organs, such as the lungs and heart, and blood clots and strokes can occur. If the ovary enlarges too much, rupture of the ovary and abdominal bleeding can occur. In rare cases, hospitalization and removal of abdominal fluid may be required to regulate fluid balance.
Fortunately, serious cases of ovarian hyperstimulation are quite rare and your doctor can predict and prevent hyperstimulation by monitoring the ovaries with ultrasound and blood estrogen levels. If we believe your risk is higher than most patients, your cycle may be cancelled. Although this is a rare event, cancellation provides complete safety, in that hyperstimulation almost never occurs after a cancelled cycle. If a cycle proceeds to egg retrieval, the risk of severe hyperstimulation may be reduced by freezing all embryos and transferring them in a later cycle, after the risk has subsided. We may also administer a medication called cabergoline, which also decreases the risk of OHSS.