close up of Man hand help woman inject drugs to prepare for IVF treatment isolated on white background, model is a asian beauty; blog: What is Ovarian Hyperstimulation Syndrome (OHSS)?When considering fertility treatments, you want to know about all of your options and the benefits and risks of the different procedures. One concern women undergoing fertility treatments sometimes have questions about is ovarian hyperstimulation syndrome.

What is OHSS?

Ovarian hyperstimulation syndrome, or OHSS, is a condition that can affect women taking injectable hormone medications during fertility treatments. The hormones that are injected are intended to stimulate the ovaries to develop multiple eggs during a menstrual cycle. It is rarely associated with fertility medications taken orally.

Fertility treatments that are sometimes associated with the condition include IVF, IUI, or other ovulation induction procedures. Only about 1% of women undergoing these treatments will experience moderate or severe symptoms and mild symptoms usually resolve themselves in a week to 10 days.


Symptoms of OHSS generally appear about 10 days after injectable hormone medications are used to stimulate ovulation. Women may experience mild, moderate, or severe symptoms that may get worse over time. On the other hand, symptoms may also improve over time. If you have even mild symptoms, you should see your doctor so you can be monitored to make sure the condition resolves itself and does not worsen.

The symptoms of ovarian hyperstimulation syndrome can include:

Mild to Moderate Symptoms

  • Mild or moderate abdominal pain
  • Abdominal tenderness in the area of the ovaries
  • Bloating in the abdomen or an increase in waist size
  • Sudden weight gain, more than 3 pounds in 2 days
  • Nausea, vomiting and/or diarrhea

Severe Symptoms

  • Rapid weight gain, 30-45 pounds in less than 10 days 
  • Severe abdominal pain
  • Enlarged or tight abdomen
  • Persistent severe nausea and vomiting
  • Shortness of breath
  • Decreased urination
  • Blood clots in legs

If the condition goes untreated, it can lead to serious complications including blood clots that travel to other organs and kidney failure.

What Causes It?

The root cause of ovarian hyperstimulation is not known, but it is linked to having high levels of HCG in the system. HCG, which stands for human chorionic gonadotropin, is a hormone usually produced during pregnancy. The blood vessels in the ovaries can have an abnormal reaction to the HCG and leak fluid, leading to swelling in the ovaries. The fluid can also leak into the abdomen.

If you are undergoing fertility treatments that include egg retrieval, HCG may be given as a shot to trigger ovulation for the retrieval. Injections of fertility drugs are more likely to cause OHSS than oral drugs like clomiphene. 

You also may be at greater risk of developing ovarian hyperstimulation syndrome if you have polycystic ovarian syndrome (PCOS), are under 30, have a large number of follicles developing, have low body weight, or have had previous episodes of hyperstimulation.

Treatment Options

Treatment should be monitored by your doctor because the condition can cause serious complications in some cases. Ultrasounds will need to be performed to keep track of the size of the ovaries and monitor any fluid in the abdomen. Blood tests are also routine to keep track of hormone levels.

You should get plenty of rest and decrease physical activity. Also, plenty of fluids with high electrolyte content. If you are experiencing nausea you might be given medication to alleviate it. 

Mild or moderate OHSS symptoms usually resolve within about two weeks unless you are pregnant. Pregnancy can make symptoms last a week or so longer, but usually resolve within three weeks and do not affect the rest of the pregnancy. You should continue to be monitored until after the symptoms have resolved.

If you do not improve with outpatient treatments, then your doctor may recommend a hospital stay so you can get IV fluids and get fluid removed from the abdomen.

Can it Be Prevented?

To prevent ovarian hyperstimulation syndrome, your doctor will monitor you during fertility treatments with ultrasounds and blood tests. If your ovaries are enlarged or your hormone levels are not in a safe range, alterations may be made to the type and doses of medication you take. Your doctor may recommend a technique known as coasting, where you stop hormone injections for a few days before getting the HCG shot to trigger ovulation. Sometimes an alternative to an HCG trigger shot will be used. Leuprolide is a common alternative.

Women undergoing IVF who experience hyperstimulation during treatment may have all follicles (mature and immature) removed during egg retrieval rather than just the mature ones. Then they can choose to have the eggs fertilized embryos frozen before taking a break to let the ovaries rest and recover. The IVF process can be resumed and they embryo transfer can be made later.

Make an Appointment

If you have questions about fertility treatments and possible side effects, Carolina Conceptions is here to help. We want to make the fertility process as smooth as possible and will hold your hand and guide you through the entire journey. To make it possible for more people to build their families, we offer physician consults monthly in Wilmington, Hampstead, and Greenville in addition to our Raleigh office. Call our main office in Raleigh at (919) 782-5911 to make an appointment.