The Fertility Foundation

Understanding Ovarian Hyperstimulation Syndrome: Symptoms, Causes, and Treatments

Understanding Ovarian Hyperstimulation Syndrome

Ovarian Hyperstimulation Syndrome (OHSS) is a condition that can occur in women undergoing fertility treatment, specifically in vitro fertilization (IVF) or ovarian stimulation. Although it is a relatively rare occurrence, it is important to understand its causes, symptoms, and available treatments. In this comprehensive guide, we will delve into the details of OHSS to provide you with a clear understanding of this condition.

What is Ovarian Hyperstimulation Syndrome?

Ovarian Hyperstimulation Syndrome (OHSS) is a medical condition that affects the ovaries in women undergoing fertility treatment. It typically occurs as a result of the ovaries being overly stimulated by fertility medications, leading to the production of a large number of eggs.

Causes of Ovarian Hyperstimulation Syndrome

The primary cause of OHSS is the administration of fertility medications to stimulate the ovaries. These medications contain hormones that encourage the production of multiple eggs, increasing the chances of successful IVF or other fertility procedures. However, in some cases, the ovaries may respond excessively to these medications, leading to OHSS.

Symptoms of Ovarian Hyperstimulation Syndrome

The symptoms of OHSS can range from mild to severe, depending on the individual case. It is crucial to recognize the signs early on to seek appropriate medical intervention. The symptoms include:

  1. Abdominal bloating and discomfort: Women with OHSS often experience a feeling of fullness or bloating in their abdominal region.
  2. Ovarian enlargement: The ovaries may become enlarged due to excessive stimulation, causing discomfort or pain in the pelvic area.
  3. Fluid retention: Fluid accumulation in the abdominal cavity can lead to weight gain and increased waist circumference.
  4. Nausea and vomiting: Some women may experience nausea and vomiting as a result of OHSS.
  5. Difficulty breathing: In severe cases, fluid accumulation in the chest cavity can lead to shortness of breath and difficulty breathing.

Types and Risk Factors of Ovarian Hyperstimulation Syndrome

OHSS can be classified into two types: early-onset and late-onset. Early-onset OHSS typically occurs within a week after fertility treatment, while late-onset OHSS may develop several weeks later, even after pregnancy has been confirmed.

Several risk factors increase the likelihood of developing OHSS, including:

  1. Younger age: Women under 30 years of age are at a higher risk of developing OHSS.
  2. Polycystic ovary syndrome (PCOS): Women with PCOS have a greater predisposition to OHSS due to their hormonal imbalances.
  3. Previous history of OHSS: Women who have experienced OHSS in previous fertility cycles are more likely to develop it again.
  4. High estrogen levels: Elevated estrogen levels during fertility treatment can increase the risk of OHSS.

Diagnosing Ovarian Hyperstimulation Syndrome

To diagnose OHSS, healthcare professionals evaluate the symptoms and perform various tests, including:

  1. Physical examination: The doctor will assess the patient’s abdomen for bloating and tenderness.
  2. Blood tests: Hormone levels, including estrogen and progesterone, will be measured to evaluate ovarian response.
  3. Ultrasound: An ultrasound scan will be performed to check the size of the ovaries and the presence of fluid in the abdominal cavity.

Treating Ovarian Hyperstimulation Syndrome

The treatment of OHSS aims to relieve symptoms, prevent complications, and promote recovery. The severity of the condition will determine the course of action, which may include:

  1. Self-care measures: Mild cases of OHSS can often be managed with rest, increased fluid intake, and over-the-counter pain relievers.
  2. Monitoring: Regular monitoring of symptoms and follow-up appointments with the healthcare provider are essential to track the progression of OHSS.
  3. Medications: In more severe cases, medications may be prescribed to help reduce ovarian swelling, relieve pain, and prevent fluid accumulation.
  4. Hospitalization: In rare instances of severe OHSS, hospitalization may be required for close monitoring and intravenous fluids to prevent dehydration.

Preventing Ovarian Hyperstimulation Syndrome

Although OHSS cannot always be prevented entirely, there are steps that can be taken to minimize the risk:

  1. Individualized treatment protocols: Fertility specialists can tailor medication dosages and protocols to reduce the likelihood of OHSS while maintaining successful treatment outcomes.
  2. Regular monitoring: Close monitoring during fertility treatment allows healthcare professionals to adjust medication dosages promptly if necessary.
  3. Freezing embryos: In cases where a high risk of OHSS is anticipated, embryos can be frozen and transferred in a subsequent cycle to reduce the likelihood of OHSS.


Ovarian Hyperstimulation Syndrome (OHSS) is a condition that can occur during fertility treatment, requiring awareness and timely intervention. By understanding the causes, symptoms, and available treatments for OHSS, individuals can navigate their fertility journey with greater confidence and make informed decisions alongside their healthcare providers. Remember, early recognition and appropriate management are key to ensuring a positive outcome and minimizing the potential risks associated with OHSS.

What is ovarian hyperstimulation syndrome (OHSS)?

OHSS is a medical condition that can occur in women undergoing fertility treatment, particularly in vitro fertilization (IVF) or ovarian stimulation. It is characterized by the ovaries being overly stimulated, leading to potential complications.

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