Ovarian Hyperstimulation Syndrome
What is Ovarian Hyperstimulation Syndrome?
Ovarian hyperstimulation syndrome is a medical condition that can happen during fertility treatments. It occurs when the ovaries respond too strongly to hormone medications used to stimulate egg production. The ovaries become swollen and painful, and they release fluid into the belly and sometimes the chest.
This condition ranges from mild to severe. Mild cases cause bloating and discomfort that goes away on its own. Severe cases can lead to serious complications like blood clots, kidney problems, and fluid buildup in the lungs. Most cases are mild, but about 1 to 2 percent of women undergoing fertility treatment develop the severe form.
The syndrome typically develops within a week after receiving hormone injections for fertility treatment. Women who become pregnant after treatment may experience worsening symptoms because pregnancy hormones can trigger additional ovarian stimulation. Understanding your hormone levels during treatment helps your doctor adjust medications to reduce your risk.
Symptoms
- Swollen and painful belly
- Nausea and vomiting
- Rapid weight gain, often 5 to 10 pounds in 3 to 5 days
- Decreased urination despite drinking fluids
- Shortness of breath
- Tight or enlarged abdomen
- Dizziness or lightheadedness
- Severe abdominal pain
- Dark-colored urine
- Chest pain or leg pain
Mild cases may only cause bloating and slight discomfort. Some women develop symptoms gradually over several days. Severe symptoms require immediate medical attention to prevent complications.
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Causes and risk factors
Ovarian hyperstimulation syndrome happens when fertility medications overstimulate the ovaries. Injectable hormone medications like human chorionic gonadotropin, or hCG, are the main triggers. These medications cause the ovaries to produce multiple eggs, but sometimes the ovaries respond too aggressively. The ovaries then release substances that make blood vessels leak fluid into surrounding tissues.
Certain factors increase your risk. Women with polycystic ovary syndrome face higher risk because their ovaries are already sensitive to hormones. Being younger than 35, having low body weight, or having high estradiol levels before receiving the trigger shot also raises risk. Previous episodes of ovarian hyperstimulation syndrome make future occurrences more likely. Using higher doses of fertility medications or retrieving a large number of eggs during treatment increases the chance of developing this condition.
How it's diagnosed
Doctors diagnose ovarian hyperstimulation syndrome based on symptoms, physical examination, and blood tests. Your fertility specialist will measure your weight and belly size during treatment visits. They will also use ultrasound imaging to check the size of your ovaries and look for fluid in your abdomen.
Blood tests play a key role in diagnosis and monitoring. Estradiol testing measures hormone levels to identify women at high risk before symptoms begin. Extremely high estradiol levels signal that the ovaries are overstimulated. Your doctor may also check kidney function, electrolyte balance, and blood cell counts to assess severity. Rite Aid offers estradiol testing that can help monitor hormone levels during fertility treatment when ordered by your healthcare provider.
Treatment options
- Stop fertility medications temporarily and delay embryo transfer if needed
- Drink plenty of fluids and electrolyte solutions to prevent dehydration
- Rest and avoid strenuous activity that could twist enlarged ovaries
- Wear loose, comfortable clothing to reduce abdominal pressure
- Monitor weight daily and report rapid gains to your doctor
- Take pain relievers like acetaminophen as directed by your doctor
- Receive intravenous fluids in hospital for moderate to severe cases
- Undergo fluid drainage if severe buildup occurs in belly or chest
- Take blood thinners to prevent clots in severe cases
- Consider freezing embryos instead of immediate transfer to reduce pregnancy-related worsening
Need testing for Ovarian Hyperstimulation Syndrome? Add it to your panel.
- Simple blood draw at your nearest lab
- Results in days, not weeks
- Share results with your doctor
Frequently asked questions
Ovarian hyperstimulation syndrome is a complication of fertility treatment where the ovaries become swollen and painful. It happens when the ovaries respond too strongly to hormone medications used to stimulate egg production. The condition can range from mild bloating to serious complications requiring hospitalization.
Mild cases affect about 20 to 33 percent of women undergoing fertility treatment. Moderate cases occur in about 3 to 6 percent of women. Severe cases are rare, affecting only 1 to 2 percent of those receiving fertility medications. Most cases resolve on their own within a week or two.
Early signs include mild belly bloating, nausea, and discomfort in the days after receiving your trigger shot. Pay attention to rapid weight gain, decreased urination, or increasing abdominal swelling. Contact your fertility clinic immediately if you gain more than 2 pounds per day or have trouble breathing.
Doctors can reduce risk by carefully monitoring estradiol levels and using lower medication doses. If your estradiol levels get too high, your doctor may cancel the cycle or delay the trigger shot. Some clinics use alternative trigger medications or freeze embryos instead of doing fresh transfers to lower risk.
Estradiol blood tests measure hormone levels during fertility treatment to identify high-risk patients. Extremely high estradiol levels before the trigger shot warn doctors that ovarian hyperstimulation may occur. Regular monitoring allows your doctor to adjust medication doses or change treatment plans to prevent severe cases.
Mild cases usually resolve within a week after egg retrieval if you do not become pregnant. If pregnancy occurs, symptoms may last several weeks as pregnancy hormones continue stimulating the ovaries. Severe cases may require hospital care for several days to a week until symptoms improve.
Severe cases can cause blood clots in the legs or lungs, kidney damage, and breathing problems from fluid in the chest. Ovarian torsion, where the enlarged ovary twists, can cut off blood supply and requires emergency surgery. Rarely, severe fluid shifts can lead to life-threatening complications requiring intensive care.
Contact your fertility clinic first for mild symptoms like bloating and nausea. Seek emergency care if you have severe abdominal pain, persistent vomiting, difficulty breathing, or chest pain. Also go to the ER if you cannot urinate, have severe leg pain or swelling, or gain more than 10 pounds in a few days.
Yes, many women with this condition still achieve pregnancy. Your doctor may freeze embryos and postpone transfer until your ovaries recover to reduce symptom severity. This approach protects your health while preserving your chances of a successful pregnancy in a future cycle.
Drink 10 to 12 glasses of fluids daily, focusing on drinks with electrolytes like sports drinks. Rest frequently and avoid heavy lifting or vigorous exercise that could twist enlarged ovaries. Eat small, frequent meals to manage nausea and choose high-protein, low-salt foods to help your body reabsorb excess fluid.