Ovarian hyperstimulation syndrome may occur after using injectable hormone medications during in vitro fertilization (IVF), a treatment for infertility. Injectable fertility medications stimulate the development of eggs in the ovaries, but it can be difficult to tell exactly how much medication you might need.
Too much of the hormone in your system can lead to ovarian hyperstimulation syndrome (OHSS), where your ovaries become swollen and painful. A small number of women may develop severe OHSS, which can cause rapid weight gain, abdominal pain, vomiting and shortness of breath.
Less often, OHSS happens during fertility treatments using medications you take by mouth, such as clomiphene. Occasionally OHSS occurs spontaneously, not related to fertility treatments.