Definition and Overview

Ovarian hyperstimulation syndrome, also known as OHSS, is a rare complication that has been observed among women who are receiving fertility treatment to stimulate egg production. It is characterized by the excessive stimulation of the ovaries, causing it to release more fluids than normal. The main danger caused by this condition is an electrolyte imbalance due to excess fluid leakage as well as long-term and serious damage to the kidneys. This condition, therefore, should not be neglected as it places the patient at risk of multi-organ dysfunction and deterioration.

Cause of Condition

Women normally produce one egg each month, but as part of the treatment for women who are having difficulty conceiving, it is possible to stimulate the ovaries to produce more eggs. However, there is a tendency for the ovaries to become excessively stimulated, causing them to become swollen.

Women who experience ovarian hyperstimulation are at risk of having some fluid leak out of the ovaries during the ovulation stage, which may affect the abdominal and chest area.

Some risk factors may increase the likelihood of a woman experiencing ovarian hyperstimulation syndrome. The risk of OHSS is higher among women who:

  • Receive a dose of human chorionic gonadotropin or hCG intravenously
  • Receive more than one dose of hCG after the ovulation stage
  • Are pregnant during the cycle
  • Have polycystic ovarian syndrome
  • Are undergoing in vitro fertilization
  • Have heightened estrogen levels during the fertility treatment
  • Are younger than age 35 at the time of the fertility treatment

Studies show that cases of OHSS affecting women taking oral fertility medications are very rare.

Key Symptoms

Women who have ovarian hyperstimulation syndrome may experience a variety of symptoms, some of which are mild and some more serious. A large percentage of women suffering from OHSS experience symptoms classified as grade 1 symptoms:

In more severe cases, symptoms classified under grade 2 of the condition may also occur; these include:

  • More severe grade 1 symptoms, i.e. abdominal pain and distention
  • Reduced urination frequency or quantity
  • Nausea
  • Diarrhea
  • Persistent vomiting
  • Unexplained weight gain of more than 10 pounds in less than five days, which is caused by ovarian enlargement between 5 and 12 cm

Serious grade 3 to grade 5 OHSS symptoms include:

  • All grades 1 and 2 symptoms
  • Breathing difficulty
  • Blood volume changes
  • Increased blood viscosity
  • Decline in renal function

These symptoms prompt doctors to conduct tests to diagnose the condition. In the case of severe symptoms, the patient may require hospitalization. While undergoing constant monitoring, the patient may undergo:

  • Abdominal or vaginal ultrasound
  • Liver function testing
  • CBC or complete blood count
  • Urine testing
  • Electrolytes panel testing
  • Chest x-ray

If left untreated, the fluid leakage from the ovaries may cause life-threatening effects, such as:

  • Kidney damage leading to kidney failure
  • Severe accumulation of excess fluid in the chest or abdominal area, or both
  • Severe electrolyte imbalance
  • Blood clot
  • Ruptured ovaries, causing hemorrhage

Who to See and Types of Treatment Available

Patients who are experiencing symptoms of ovarian hyperstimulation and are subject to the risk factors mentioned above should consult a general physician or a gynecologist for treatment.

In most mild cases of ovarian hyperstimulation, treatment is not necessary and the condition may be considered as a side effect of the fertility treatment. In fact, some studies show that mild OHSS means that the fertility treatment is working and may thus improve the woman’s chance of conceiving. Any symptoms that may occur tend to disappear after a few days or when the woman has her menstrual period.

However, if the discomfort caused by OHSS is causing the patient some trouble, some home remedies and self-care techniques may be beneficial. Patients are advised to:

  • Get plenty of rest while maintaining some light activity
  • Elevate their legs to help the body release the excess fluid released by the ovaries
  • Drink 10 to 12 glasses of fluids per day, preferably fluids that can help replenish the body’s electrolyte levels
  • Refrain from consuming alcohol and other caffeinated beverages
  • Avoid strenuous activities
  • Avoid sexual intercourse
  • Check their weight every day

They can also ask their attending physician whether it is advisable to take a pain reliever to help with the discomfort.

However, in severe cases, patients are admitted to a hospital. During hospitalization, the goals of treatment are:

  • Removal of any excess fluids that have leaked out from the ovaries
  • Replenishment of the body’s fluid and electrolyte levels, which is done intravenously

The condition of women suffering from more severe ovarian hyperstimulation can be expected to improve after several days. The symptoms, however, may become prolonged if the patient becomes pregnant while suffering from OHSS.

Surgical treatment is rarely needed, but may become necessary if there is an ovarian torsion, an ovarian cyst ruptures, or there’s hemorrhage.


  • Lobo RA. Infertility: etiology, diagnostic evaluation, management, prognosis In: Lentz GM, Lobo RA, Gershenson DM, Katz VL, eds. Comprehensive Gynecology. 6th ed. Philadelphia, PA: Elsevier Mosby; 2012:chap 41.

  • Schorge JO, Schaffer JI, Halvorson LM, et al. Treatment of the infertile couple. In: Cunningham FG, Leveno KL, Bloom SL, et al, eds. Williams Obstetrics. 23rd ed. New York, NY: McGraw-Hill; 2010:chap 20.

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