Ovarian hyperstimulation syndrome (OHSS) is a complication occasionally seen in women who take certain fertility medicines that stimulate egg production.

See also: Infertility

Normally, a woman produces one egg per month. Some women undergoing fertility treatments are given medicines to help normalize egg development or increase egg production.

However, if the drugs stimulate the ovaries too much, the ovaries can suddenly become very swollen and fluid can leak into the belly and chest area. This is called ovarian hyperstimulation syndrome (OHSS). OHSS occurs only after the eggs are released from the ovary (ovulation).

You may be more likely to get OHSS if your doctor gives you an injection of a hormone called human chorionic gonadotropin (hCG) to help trigger ovulation. You may have an even greater risk of this syndrome if you receive more than one dose of hCG after ovulation. OHSS rarely, if ever, occurs in women who only take fertility medicines by mouth.

OHSS affects up to 10% of women who go through in vitro fertilization. In most cases the condition is mild, but some women get a severe and dangerous form of OHSS.

Additional risk factors for OHSS include:

• Age younger than 35
• Very high estrogen level while undergoing fertility treatments
• Polycystic ovarian syndrome

The symptoms of OHSS can range from mild to severe. Most women with the condition have mild symptoms such as:

• Abdominal bloating
• Mild pain in the abdomen
• Weight gain

In rare cases, women can have more serious symptoms, including:

• Significant weight gain (more than 10 pounds in 3 - 5 days)
• Severe pain or swelling in the abdomen
• Decreased urination
• Shortness of breath

If you have a severe case of OHSS, your health care provider will need to carefully monitor your symptoms. You may be admitted to the hospital.

Your weight and size of your belly area (abdomen) will be measured. Tests that may be done include:

• Abdominal ultrasound or vaginal ultrasound
• Chest x-ray
• Complete blood count
• Electrolytes panel
• Liver function test
• Tests to measure urine output

Mild cases of OHSS usually don't need to be treated. You can ease your discomfort by doing the following:

• Get plenty of rest with your legs raised. This helps your body release the fluid.
• Drink at least 10 - 12 glasses of fluid a day (especially drinks that contain electrolytes).
• Avoid alcohol or caffeinated beverages (such as colas or coffee).
• Avoid intense exercise and sexual intercourse, which can cause ovarian discomfort and may cause ovarian cysts to rupture or leak.
• Take an over-the-counter pain reliever, such as acetaminophen (Tylenol).

You should weigh yourself each day to make sure you're not putting on too much weight (5 or more pounds a day).

In the rare case that you develop severe OHSS, you will probably need to go to a hospital. The health care providers there will give you fluids through a vein (intravenous fluids), remove fluids that have collected in your body, and monitor your condition.

Most mild cases of OHSS will go away on their own after menstruation starts. If you have a more severe case, it can take several days for symptoms to improve.

If you become pregnant during OHSS, the symptoms may get worse and can take weeks to go away.

In rare cases, OHSS can lead to life-threatening complications, including:

• Blood clots
• Kidney failure
• Severe electrolyte imbalance
• Severe fluid build-up in the abdomen or chest

Call your healthcare provider if you experience any of the following symptoms:

• Excessive weight gain (more than 5 pounds a day)
• Severe abdominal pain
• Nausea so intense that you can't keep food or liquids down
• Decreased urination
• Shortness of breath
• Dizziness

If you are receiving injections of fertility medicines, your doctor will monitor you carefully with blood tests and pelvic ultrasounds to make sure that your ovaries aren't over-responding.

If your estrogen level rises very high or very quickly while taking fertility injections, your risk for OHSS is increased. You may need to take a lower dose of the medicines or temporarily stop treatment.

Some women may be given a protein solution called albumin to reduce the chances of OHSS.

Ovarian hyperstimulation syndrome. Fertil Steril. November 2003;80(5):1309-1314.

Budev MM, Arroliga AC, Falcone T. Ovarian hyperstimulation syndrome. Crit Care Med. 2005;33:S301-S305.