Ovarian hyperstimulation syndrome is the overstimulation of the ovaries that may occur as a result of assisted reproductive technology (ART). ART is a type of infertility treatment that uses multiple eggs at one time to raise the chances of producing embryos that are good candidates for fertilization.

Before an ART procedure, a woman uses medicine or hormones to stimulate multiple egg production (superovulation). The eggs are then collected for laboratory use. In a small number of ART cycles, superovulation overstimulates the ovaries. This problem is called ovarian hyperstimulation syndrome.

Doctors watch closely for signs of ovarian hyperstimulation during superovulation. When this condition occurs, the medicine is stopped. Any procedure, such as egg collection, planned for that particular cycle is postponed until all symptoms are gone, usually in 2 to 4 weeks.

Ovarian hyperstimulation syndrome can be mild, moderate, or severe:

• Mild hyperstimulation causes enlargement of the ovaries and discomfort and fluid buildup in the abdomen.
• Moderate hyperstimulation causes additional symptoms including nausea, vomiting, and shortness of breath. This condition may require bed rest.
• Severe hyperstimulation can cause life-threatening fluid buildup around the heart and lungs and in the abdomen, and a drop in blood fluid content. This condition requires urgent medical care and hospitalization to prevent liver failure, stroke, or heart damage.