Ovarian hyperstimulation Syndrome (OHSS)

ovarian hyperstimulation syndrome OHSS block letters

Ovarian hyperstimulation syndrome (OHSS) causes swelling of the ovaries, which leak fluid within the body. This condition occurs in women who receive fertility treatments that stimulate the ovaries to produce more eggs. 

OHSS develops because of high levels of the pregnancy hormone HCG following these fertility treatments. PCOS and the use of fertility treatments increase the risk of OHSS. 

Drugs used in fertility treatments cause the blood vessels surrounding the ovaries to leak fluid. This fluid causes the ovaries to swell. Sometimes this fluid moves into the belly and other areas, causing:

  • Swelling

  • Pain

  • Nausea

  • Vomiting

  • Increased thirst

In severe forms, the excess fluid can result in difficulty breathing and decreased urination.

OHSS used to occur in about 10% of women who receive in-vitro fertilization treatments, but today the number is less than 5%. When it occurs, OHSS is usually temporary and resolves within 1-2 weeks. 

OHSS Symptoms

OHSS symptoms woman with nausea

Symptoms of ovarian hyperstimulation syndrome often begin within a week after using injectable medications of HCG to stimulate ovulation, though sometimes it can take two weeks or longer for symptoms to appear. If you become pregnant during a treatment cycle, OHSS may worsen as your body begins producing its own HCG in response to the pregnancy.

The signs and symptoms of OHSS vary depending on the severity of the condition. Symptoms of mild to moderate OHSS include:

  • Abdominal discomfort/pain

  • Bloating

  • Slight weight gain

  • Nausea

Severe cases of OHSS occur rarely and can lead to hospitalization due to serious symptoms and complications including:

  • Excessive weight gain

  • Severe nausea and vomiting

  • Severe abdominal swelling

  • Difficulty breathing

  • Blood clots

  • Decreased urination

  • Kidney failure

Home Remedies

If you develop mild ovarian hyperstimulation syndrome, you'll probably be able to continue your day-to-day routine with these recommendations. However, always contact your doctor for any specific concerns or advice. 

  • Try an over-the-counter painkiller such as acetaminophen (Tylenol) for abdominal discomfort, but avoid ibuprofen (Advil, Motrin IB) or naproxen sodium (Aleve) if you have recently had an embryo transfer, as these drugs can interfere with implantation of the embryo.

  • Maintain a light physical activity level, avoiding strenuous or high-impact activities.

  • Weigh yourself on the same scale and measure around your abdomen each day, reporting unusual increases to your doctor.

  • Avoid sexual intercourse, as it may be painful and can cause a cyst in your ovary to rupture.

  • Call your doctor if your signs and symptoms get worse.

Strategies to Prevent OHSS

  • Adjusting medication. Your doctor uses the lowest possible dose of gonadotropins to stimulate your ovaries and trigger ovulation.

  • Adding medication. Some medications seem to reduce the risk of OHSS without affecting the odds of pregnancy. These include low-dose aspirin; dopamine agonists such as cabergoline or quinagolide, and calcium infusions. Giving women who have polycystic ovary syndrome, the drug metformin during ovarian stimulation may also help prevent hyperstimulation. 

  • Coasting. If your estrogen level is high or you have a large number of developed follicles, your doctor may have you stop injectable medications and wait a few days before giving HCG, which triggers ovulation. This is known as coasting.

  • Avoiding the use of an HCG trigger shot. Because OHSS often develops after an HCG trigger shot is given, alternatives to HCG for triggering have been developed using Gn-RH agonists, such as leuprolide (Lupron), as a way to prevent or limit OHSS.

  • Freezing embryos. If you're undergoing IVF, all the follicles (mature and immature) may be removed from your ovaries to reduce the chance of OHSS. Mature follicles are fertilized and frozen, and your ovaries are allowed to rest. You can resume the IVF process at a later date when your body is ready.

Preparing for a Doctor’s Appointment

Depending on how severe your ovarian hyperstimulation syndrome is, your first appointment may be with your primary care provider, your gynecologist or infertility specialist, or possibly with a treating doctor in the emergency room.

If you have time to prepare for your appointment, you should: 

  • Write down any symptoms you're experiencing. 

  • Make a list of any medications and vitamin supplements you take including doses and how often you take them.

  • Have a family member or close friend go with you if possible. You may become overwhelmed with information at your visit, and it can be difficult to remember everything. If you can’t bring a friend, bring a notebook to write important information.

  • Prepare a list of questions to ask your doctor including any concerns about symptoms you’ve been experiencing. 

Some potential questions your doctor might ask you include:

  • When did your symptoms begin?

  • How severe are your symptoms?

  • Does anything make your symptoms better?

  • Does anything seem to make your symptoms worse?

Getting Diagnosed

Doctors diagnose OHSS with several tests:

Physical exam: Your doctor will check your weight and measure the size of your waist to look for signs of swelling. You will also want to discuss any abdominal pain you may have.

Ultrasound: This test looks for free fluid in the abdomen and the size of the ovaries. If you have OHSS, an ultrasound may show that your ovaries are bigger than normal, with large fluid-filled cysts where follicles developed. During treatment with fertility drugs, your doctor regularly evaluates your ovaries with a vaginal ultrasound.

Chest X-ray: This is used to look for fluid in the chest.

Blood test: A blood test will measure hormone levels for signs of OHSS. Certain blood tests also allow your doctor to check for abnormalities in your blood and whether your kidney function is being impaired because of OHSS.

Treatments

The treatment for OHSS varies depending on how severe the condition is. Treatment aims to manage symptoms and avoid complications.

For mild to moderate cases of OHSS, treatment usually involves:

  • Avoiding vigorous physical activity

  • Increasing fluids

  • Using acetaminophen to relieve symptoms

  • Weighing yourself daily

  • Monitoring yourself for any severe symptoms

  • Frequent physical exams and ultrasounds

  • Blood tests to monitor for dehydration, electrolyte imbalance, and other problems

  • Medications to prevent blood clots (anticoagulants)

Severe cases of OHSS often require hospitalization for monitoring and aggressive treatment, including IV fluids. Your doctor may give you a medication called cabergoline to lessen your symptoms. Sometimes, your doctor may also give you other medications, such as gonadotropin-releasing hormone (Gn-RH) antagonist or letrozole (Femara), to help suppress ovarian activity.

Other treatments of severe OHSS may include:

  • Adjusting your fertility medication dose

  • Freezing your embryos and delaying their embryo transfer until the ovaries return to normal

  • Undergoing paracentesis (a procedure to remove fluid from the belly)

Serious complications from ovarian hyperstimulation syndrome may require additional treatments, such as surgery for a ruptured ovarian cyst or intensive care for liver or lung complications. You may also need anticoagulant medications to decrease the risk of blood clots in your legs.

 

Sources: American Society for Reproductive Medicine, "Fact Sheet: Side-effect of injectable fertility drugs," revised 2012. Insler, V et al. "Prevention of ovarian hyperstimulation syndrome." UpToDate, reviewed February 2014. Cleveland Clinic. Mayo Clinic.