Ovarian Hyperstimulation Syndrome (OHSS)

Ovarian Hyperstimulation Syndrome (OHSS) is a potential complication of IVF that occurs as a result of taking ovulation-stimulating medications. In this syndrome, the ovaries become swollen and fluid leaks into the body. OHSS is more commonly seen in women with Polycystic Ovary Syndrome (PCOS) who are undergoing infertility treatment. In the past, OHSS was a common complication of IVF, but with more precise protocols and drug strategies, the occurrence of severe OHSS has become very rare. Most cases are mild and cause no problems, but severe cases can be life-threatening.

Prevalence of OHSS: In the past, the prevalence of OHSS in women undergoing IVF cycles was more than 10%, but it has now dropped to less than 5%. The prevalence of severe and dangerous cases of OHSS is also less than 1% and very rare.

Causes of OHSS: In most cases, this complication occurs due to an excessive increase in the pregnancy hormone (hCG), which is induced by taking ovulation-stimulating medications to obtain a large number of eggs in one cycle for IVF. In very rare cases, genetic mutations in certain hormone receptors can cause OHSS without any medication. Ovulation-stimulating drugs cause the blood vessels surrounding the ovaries to leak fluid, sometimes into the abdomen or other areas, leading to symptoms such as swelling, pain, nausea, vomiting, and increased thirst. Severe cases may also lead to respiratory problems and reduced urine output.

Symptoms of OHSS: Symptoms vary depending on the severity of the syndrome. Mild to moderate cases usually present with:

• Abdominal pain
• Abdominal swelling and bloating
• Weight gain
• Nausea

In severe cases, symptoms may include:

• Severe weight gain
• Severe nausea and vomiting
• Severe abdominal swelling
• Breathing problems
• Blood clots
• Reduced urine output
• Kidney failure
• Severe abdominal pain

Diagnosis of OHSS: OHSS can be diagnosed through various methods, including:

• Examination: Measuring weight and waist circumference to check for abdominal swelling
• Ultrasound: To check for free fluid in the abdomen and pelvis and to assess the size of the ovaries
• Chest X-ray: To check for fluid in the chest
• Blood tests: To check hormone levels

Treatment or management of OHSS: Treatment depends on the severity of the symptoms. The main goal is to manage symptoms and prevent further complications. In mild to moderate cases, symptoms gradually reduce and disappear, and it is usually recommended to:

• Avoid strenuous activities
• Increase fluid intake
• Take simple painkillers (acetaminophen) to reduce symptoms
• Monitor weight daily
• Watch for symptoms to prevent worsening

In severe cases, hospitalization is usually required. Treatment for severe OHSS may include:

• Adjusting the dose of infertility treatment medications
• Intravenous fluids (IV drip)
• Freezing embryos and postponing embryo transfer to later cycles (until the ovaries return to normal)
• Draining free fluid in the abdomen
• Prescribing medications to reduce symptoms or decrease ovarian activity

If you experience symptoms, even mild ones, be sure to contact your doctor. In case of severe symptoms, do not hesitate to go to the hospital.