Ovarian Hyperstimulation Syndrome (OHSS) and IVF: Risks, Complications and Treatment

Ovarian Hyperstimulation Syndrome (OHSS) and IVF: Risks, Complications and Treatment

OHSS is the most dangerous complication of IVF treatment. Learn about OHSS risk factors and expert tips on how to prevent OHSS and treat it from a fertility expert.

During IVF fertility medications are used to mature several eggs at the same time. Some women however are very sensitive to these medications. These women can produce a large number of eggs, which is good, but they can also develop a problem called OHSS or ovarian hyperstimulation syndrome, which is rare but potentially life-threatening.

ohss ivf treatment

Fertility drugs are used for IVF

Human beings produce a lot of abnormal embryos that do not have the ability to produce a live born baby. In order to get around this problem, IVF experts use fertility medications to help women mature many eggs at the same time.

We know that more eggs means the possibility of making more embryos and this increases the odds of finding a few healthy normal embryos that can produce a pregnancy.

Fertility drug injections

The most common fertility medications used during IVF are injections of hormones called Gonadotropins. These medications contain the same hormones that the pituitary gland makes to mature eggs in the ovaries naturally.

There are several different brand names for these medications but they all have the same risk of OHSS. 

What causes OHSS? 

To understand what causes OHSS it is important to understand that every egg in the ovary is contained in a tiny cyst called a follicle. You can see some of the larger follicles when you do an ultrasound of the ovaries. These follicles are made up of millions of cells. These cells produce many different hormones and compounds that are released into the blood.

VEGF makes blood vessels leaky

One of these compounds is called VEGF. VEGF makes your blood vessels leak. Leakage of fluid out of the blood vessels is responsible for most of the problems associated with OHSS.

Using fertility medications increases the number of follicles that develop and increases VEGF.

Who is at risk for developing OHSS?

  • Women who are young
  • Women who are thin
  • Women who don't ovulate regularly
  • Women with PCOS

However any woman who takes fertility medications and develop OHSS, though it is less likely in women not in those groups. Although it is not possible to prevent OHSS a hundred percent of the time, IVF experts can utilize several methods to help reduce your risk. We can break these down into steps:

  • Before you start fertility medications
  • While you are taking them
  • After the egg retrieval

Steps to preventing OHSS before starting fertility drugs

Before starting medication your doctor should check the levels of a hormone in your blood called AMH. Women with higher AMH levels are more sensitive to fertility medications. The doctors should reduce the dose of fertility medications in women with high AMH levels. Some studies showed that taking a medication called Metformin two months before starting the fertility medications can reduce the chances of developing OHSS.

Steps to prevent OHSS while taking fertility drugs

While taking the fertility medications, your doctor should monitor you closely with blood tests and ultrasound. If your doctor sees that you are responding very vigorously, they can start to make adjustments like further reducing the dose of medications and monitoring you more frequently.

The last medications that a woman takes before the egg retrieval are called the trigger injections. In women who are at high risk for OHSS, doctors should consider making changes to the trigger injections, such as reducing the dose of hCG to help reduce VEGF production.

It is also a good idea to start another medication called Cabergoline which can block the effects of VEGF.

cabergoline ohss drugs medication treatment

Timing and Symptoms of OHSS

It is only after the egg retrieval is completed that the symptoms of OHSS start to develop the more eggs that were retrieved the higher the chances for developing OHSS.

Symptoms of OHSS include:

  • weight gain increase in bloating and abdominal pressure
  • shortness of breath
  • decreased urination 
  • nausea and vomiting

Steps to prevent OHSS after taking fertility drugs

Despite all of the precautions I discussed before, if your doctor thinks that you are still at high risk for developing OHSS after the egg retrieval, then you should avoid doing an embryo transfer and freeze all of your embryos instead.

embry freezing ohss

Why? Well, if you do an embryo transfer and become pregnant, the hCG produced from the pregnancy will continue to stimulate your ovaries and make the problems worse.

If you do develop OHSS and too much fluid leaks out of your blood vessels, your blood will get thicker and more prone to blood clots, which can cause severe problems like a stroke.

It is very important to take medications to reduce the chance for blood clots to form.

Finally much of the fluid that leaks out of your blood vessels will settle in your abdomen. Your doctor can drain fluid from your abdomen in much the same way as when you have an egg retrieval. This can help you feel better right away and can speed up the time it takes for the problem to resolve.