What is (OHSS) Ovarian Hyperstimulation Syndrome?

Ovarian Hyperstimulation Syndrome: What It Is and How It’s Treated

To increase the effectiveness of assisted reproduction treatments like in vitro fertilization (IVF), we need to stimulate the ovaries to produce a larger number of mature eggs. However, in some cases, despite taking the proper precautions, a patient may have an exaggerated ovarian response—typically when more than 18 or 20 eggs are produced. This can lead to what is known as Ovarian Hyperstimulation Syndrome (OHSS).

In its severe form, OHSS affects about 1% of women undergoing IVF after receiving a medication called Ovitrelle, which is used to trigger egg maturation. The condition can range from mild to moderate to severe and may cause symptoms like nausea, vomiting, abdominal bloating, fluid accumulation in the abdomen, and reduced urine output. In more serious cases, it may also lead to breathing difficulties, liver and kidney dysfunction, and even blood clotting issues.There are two types of OHSS: early and late onset. Early OHSS appears 2–3 days after egg retrieval and up to 9 days after Ovitrelle is administered. Late OHSS occurs more than 9 days post-Ovitrelle and is related to rising Beta hCG pregnancy hormone levels.

Are Some Women at Higher Risk for Ovarian Hyperstimulation Syndrome?

Yes. Women at increased risk of developing OHSS include:

Younger women
Women with low body weight
Women with allergies
Women with a history of Polycystic Ovary Syndrome (PCOS)
Women with high ovarian reserve
Women who have experienced OHSS in a previous cycle

How Does OHSS Progress?

OHSS is usually self-limiting. That means the symptoms typically appear, peak, and then resolve on their own within 7 to 10 days. During this time, patients are closely monitored to assess how the condition evolves.

Can Ovarian Hyperstimulation Syndrome Be Prevented?

Yes. Today, there are strategies available to prevent or reduce the severity of OHSS, especially for patients identified as high risk. These measures are personalized based on each individual’s medical profile and fertility treatment plan.

How Is OHSS Treated?

In mild cases of OHSS, symptoms may be confused with typical IVF side effects like nausea, abdominal bloating, and general discomfort. Treatment includes relative rest, proper hydration, pain relief, and anti-nausea medications, depending on the symptoms.

Moderate OHSS is marked by fluid accumulation in the abdomen (ascites). In addition to the above measures, the patient requires monitoring every 24–48 hours. This includes checking general health status, urine output, amount of ascitic fluid, and blood test results. Heparin may be prescribed as a blood thinner if there’s a risk of thrombosis.

Finally, severe OHSS requires hospitalization to manage hydration, monitor kidney and liver function, and ensure proper respiratory function.

Have you heard of OHSS before? Are you considering assisted reproduction treatment and want to know more? At URE Centro Gutenberg, we take patient education very seriously. Making sure you have clear answers is a key part of our job. If you’d like to know more, book an appointment with us and we’ll help resolve all your questions.