Ovarian hyperstimulation syndrome involves painful, swollen ovaries. It may occur after use of injectable hormone medications during in vitro fertilization (IVF), a treatment for infertility. Less often, it occurs during fertility treatment with oral medications.

Symptoms often begin within a week after using injectable fertility medication, though it could be two weeks or longer. Symptoms can range from mild to severe and may include abdominal pain, bloating, increased waist size, rapid weight gain, nausea, vomiting, diarrhea and ovarian tenderness.

It often clears up on its own. A severe case needs hospital care.