What should you know about spontaneous ovarian hyperstimulation syndrome?

Ovarian hyperstimulation syndrome, or OHSS, involves enlarged ovaries and increased blood-vessel leakiness. Fluid can move into the abdomen and, in more serious illness, affect breathing, circulation, or kidney function. The spontaneous form is not triggered by the medicines commonly used to stimulate ovulation.

It can be associated with early pregnancy or an underlying tendency for the ovaries to respond strongly to hormonal signals. Symptoms may include abdominal swelling or pain, nausea, vomiting, rapid weight change, and reduced urine. These symptoms overlap with other conditions, so assessment is needed.

Contact your fertility or maternity team if abdominal swelling, pain, vomiting, or breathlessness develops, especially after a positive pregnancy test. Keep a record of symptoms, fluid intake, urine output, and any change in weight if the team asks you to monitor them. Do not start diuretics, pain medicines, or supplements without advice.

The team may examine you, arrange ultrasound and blood tests, and monitor fluid balance. Treatment can include observation, symptom relief, fluid guidance, prevention of blood clots, or hospital care when illness is more severe. A later frozen embryo transfer may be discussed in some fertility plans to avoid additional ovarian stimulation.

Go to urgent care for difficulty breathing, chest pain, fainting, severe or rapidly worsening abdominal pain, inability to keep fluids down, very little urine, or a painful swollen leg. These symptoms can signal fluid complications, dehydration, bleeding, or a clot and need prompt evaluation.

What findings would confirm OHSS, and how often should I be reviewed? Which symptoms mean hospital assessment is needed? Could pregnancy or an ovarian condition be contributing, and how would this affect my fertility plan?