Ovarian Hyperstimulation Syndrome

What is Ovarian Hyperstimulation Syndrome?

Ovarian Hyperstimulation Syndrome (OHSS) is characterized by painfully swollen ovaries. In a majority of cases it is brought on by intravenous hormone fertility treatments, but in rare instances it can occur while taking oral fertility meds. Even more rarely it can occur naturally. Mild cases are quite common while undergoing IV fertility treatments.

High levels of the pregnancy hormone HCG can cause ovarian blood vessel leakage. The excess fluid causes swelling, and in more serious cases it can enter into the abdominal cavity. The condition can significantly worsen if pregnancy occurs during treatment because of increasing HCG levels. Life-threatening complications occur very rarely.

What are the Symptoms of Ovarian Hyperstimulation Syndrome?

The symptoms of ovarian hyperstimulation can range from mild to severe. Symptoms of mild to moderate ovarian hyperstimulation syndrome may include:

  • Slight to moderate abdominal discomfort or pain
  • Bloating
  • Queasiness
  • Vomiting
  • Loose stools
  • Tender ovaries

More serious symptoms may include:

  • Fast weight increase
  • Excruciating abdominal pain
  • Unrelenting queasiness and vomiting
  • Reduced urine output
  • Darkened urine
  • Breathing difficulties
  • Distended abdomen
  • Dizziness
  • Leg pain

Ovarian Postulation Syndrome Causes

Ovarian hyperstimulation syndrome (OHSS) is caused by fertility drugs which are used during IVF treatment. The drugs are designed to stimulate the growth of eggs, but in some cases, they can cause overstimulation of the ovaries which subsequently begin to enlarge.

The enlarged ovaries then release chemicals which enter the bloodstream. At this point, fluid begins to leak from blood vessels into the abdomen and sometimes into the mediastinum, which is the area surrounding the heart and lungs.

OHSS is relatively common, with around 33% of women experiencing a mild form of the syndrome during IVF. However, only a very small proportion – around 1% – will experience severe OHSS. Sometimes other factors are involved which contribute to the syndrome. For example, women with polycystic ovarian syndrome (PCOS) are at a higher risk of OHSS during IVF, as are those who are aged 30 or younger. Women with a particularly low body weight are also at an increased risk.

How is Ovarian Hyperstimulation Syndrome Treated?

Treatment of ovarian hyperstimulation syndrome is usually unnecessary, but in moderate cases it may include:

  • Over-the-counter or prescription pain medication
  • Anti-nausea medication
  • Weight monitoring
  • Daily urine measurements
  • Blood monitoring
  • Increased fluid intake
  • Drainage of abdominal fluid
  • Support hosiery to prevent blood clotting
  • Avoidance of rigorous physical activities and sexual intercourse

Treatment for serious complications of ovarian hyperstimulation syndrome may include hospitalization, intravenous fluids, anticoagulants, medication to counter the effects of HCG and surgical repair of a ruptured ovarian cyst. Intensive care may be necessary in the treatment of serious lung and liver problems.

Ovarian Postulation Syndrome Prevention

Clinicians may recommend alternative fertility treatments or medications, or lower dosages for women who seem at a particularly high risk of OHSS. However, in many cases, it isn’t possible to prevent the syndrome.

Women who have been diagnosed with OHSS should get plenty of rest and avoid sexual intercourse or exercise. This is because the ovaries will be enlarged and painful and you must take care to prevent injury.

In rare, severe cases of OHSS, thrombosis can occur. This is where blood clots develop in the deep veins of the legs or in the lungs. To prevent this, women may be given injections of heparin to thin the blood and reduce the risk of clotting. Support stockings may also be worn to help prevent thrombosis in the legs.

Last Reviewed:
September 21, 2016
Last Updated:
January 24, 2018