Ovarian Hyperstimulation Syndrome (OHSS): Symptoms, Causes, Treatment

What are the symptoms of ovarian hyperstimulation syndrome?

Ovarian Hyperstimulation Syndrome (OHSS) is a condition that can occur in women undergoing fertility treatments, particularly those that involve stimulating the ovaries, such as in vitro fertilization (IVF). It happens when the ovaries respond excessively to hormonal medications, causing them to swell and leak fluid into the body. Symptoms can range from mild to severe.

Symptoms of Ovarian Hyperstimulation Syndrome (OHSS)

Mild to Moderate Symptoms:

• Abdominal bloating or discomfort
• Mild to moderate abdominal pain
• Nausea and vomiting
• Diarrhea
• Weight gain (usually rapid, up to 2–5 pounds in a day)
• Enlarged ovaries, which may be tender
• Increased urination

Severe Symptoms:

• Severe abdominal pain or swelling
• Rapid weight gain (more than 10 pounds in 3 to 5 days)
• Severe nausea and vomiting
• Shortness of breath or difficulty breathing
• Decreased urination or dark urine, indicating dehydration
• Severe bloating or distention
• Leg swelling (edema)
• Dizziness or fainting
• Blood clots, usually in the legs
• Rapid heartbeat

When to Seek Medical Attention:

If any of the severe symptoms are present, especially difficulty breathing, rapid weight gain, or significantly reduced urination, immediate medical attention is necessary. Severe OHSS can lead to complications such as kidney failure, fluid accumulation in the chest or abdomen, and blood clots.

OHSS is more likely to occur in women with certain risk factors, such as polycystic ovary syndrome (PCOS) or higher doses of fertility drugs.

What are the causes of ovarian hyperstimulation syndrome?

Ovarian Hyperstimulation Syndrome (OHSS) is primarily caused by an exaggerated response to fertility medications that stimulate the ovaries to produce multiple eggs. These medications are typically used in assisted reproductive technologies like in vitro fertilization (IVF). The exact cause of OHSS is not fully understood, but several key factors are known to contribute to the condition:

1. Use of Fertility Medications

• Gonadotropins (hormonal medications): These medications, such as human chorionic gonadotropin (hCG), follicle-stimulating hormone (FSH), and luteinizing hormone (LH), stimulate the ovaries to produce multiple eggs during a fertility treatment cycle.
  • hCG is often used to trigger ovulation, and it can lead to a surge in hormones that cause the ovaries to become enlarged and release fluids.
• Clomiphene citrate (Clomid): This oral medication, though less likely to cause OHSS, may still lead to overstimulation of the ovaries in some women.

2. Excessive Response to Fertility Drugs

• Some women may be more sensitive to fertility drugs, leading to overstimulation of the ovaries, causing them to release excessive amounts of hormones. This overstimulation can result in the development of multiple follicles (fluid-filled sacs containing eggs), which leads to OHSS.

3. High Levels of hCG

• When high doses of hCG are used to trigger ovulation, it can cause blood vessels in the ovaries to leak fluid into the abdomen and chest, leading to swelling and fluid buildup.
• hCG from pregnancy: If a woman becomes pregnant after fertility treatments, her body naturally produces hCG, which can worsen OHSS symptoms. OHSS tends to become more severe if pregnancy occurs.

4. Risk Factors in Certain Women

Some women are more prone to developing OHSS due to certain pre-existing conditions or risk factors:

• Polycystic Ovary Syndrome (PCOS): Women with PCOS, who naturally have multiple small cysts on their ovaries, are more likely to develop OHSS.
• Young age: Younger women, especially under the age of 35, tend to have a stronger response to fertility medications.
• Low body weight: Women with a lower body mass index (BMI) are at a higher risk.
• History of OHSS: Women who have experienced OHSS in previous fertility treatments are more susceptible.
• High estrogen levels: Elevated levels of estradiol, a form of estrogen, during ovarian stimulation can increase the likelihood of OHSS.
• Multiple follicles: A large number of developing follicles, particularly more than 20, raises the risk of OHSS.

5. Vascular and Inflammatory Responses

• OHSS is believed to involve the release of substances like vascular endothelial growth factor (VEGF), which causes blood vessels to become more permeable, leading to fluid leakage into the abdomen and surrounding tissues. This results in fluid accumulation (ascites), swelling, and other symptoms.

6. Egg Retrieval and Assisted Reproductive Techniques

• In procedures like IVF, where multiple eggs are retrieved after stimulation, the ovaries may become overstimulated and enlarge, contributing to the onset of OHSS.

Summary of Causes:

• Fertility medications (especially gonadotropins and hCG)
• High estrogen levels and multiple developing follicles
• Underlying conditions such as PCOS
• Excessive hormonal response, particularly from hCG, during ovulation or early pregnancy

Careful monitoring of ovarian response during fertility treatment can help reduce the risk of OHSS. Adjusting medication doses or freezing embryos for later use in future cycles (instead of immediately transferring them) are strategies often employed to prevent or manage OHSS.

How is the diagnosis of ovarian hyperstimulation syndrome made?

The diagnosis of ovarian hyperstimulation syndrome (OHSS) is typically made through a combination of clinical assessment, patient history, and laboratory tests. Here are the key components of the diagnostic process:

1. Patient History:

• Fertility Treatment History: The healthcare provider will review the patient’s history of fertility treatments, including the types of medications used, dosages, and duration.
• Symptom Review: The provider will assess the presence and severity of symptoms such as abdominal bloating, pain, nausea, vomiting, and weight gain.

2. Clinical Examination:

• Physical Exam: A physical examination will be conducted to check for abdominal distension, tenderness, and signs of fluid accumulation, such as swelling in the legs or feet.
• Vital Signs: The healthcare provider may monitor vital signs such as blood pressure and heart rate, as changes can indicate severe OHSS.

3. Laboratory Tests:

• Blood Tests: Blood tests may be performed to evaluate:
• Electrolyte levels: Imbalances in electrolytes such as sodium and potassium can occur with OHSS.
• Kidney function: Blood urea nitrogen (BUN) and creatinine levels may be assessed to evaluate kidney health.
• Hematocrit levels: Elevated hematocrit can indicate hemoconcentration due to fluid shifts.
• Estrogen levels: High levels of estradiol may support a diagnosis of OHSS.

4. Imaging Studies:

• Ultrasound: Pelvic ultrasound can be used to visualize the ovaries and assess the number and size of follicles. Signs of OHSS may include enlarged ovaries (often greater than 5 cm) and fluid accumulation in the abdominal cavity (ascites).

Classification of Severity:

OHSS is classified into three categories based on symptoms and clinical findings:

• Mild: Mild abdominal discomfort or bloating, with no significant weight gain or serious complications.
• Moderate: Increased abdominal size, more significant pain, shortness of breath, and possibly more notable weight gain (e.g., 5-10 lbs or 2.3-4.5 kg).
• Severe: Severe abdominal pain, significant weight gain (more than 10 lbs or 4.5 kg), respiratory difficulties, and signs of complications such as dehydration or kidney impairment.

Conclusion

If you are undergoing fertility treatment and experience symptoms suggestive of OHSS, it is important to notify your healthcare provider promptly. Early diagnosis and management are crucial in preventing potential complications. Your healthcare team will use the above methods to determine the diagnosis and recommend appropriate treatment based on the severity of the condition.

What is the treatment for ovarian hyperstimulation syndrome?

The treatment for ovarian hyperstimulation syndrome (OHSS) depends on the severity of the condition. Management primarily focuses on alleviating symptoms, monitoring, and preventing complications. Here’s a breakdown of the treatment approaches based on severity:

1. Mild OHSS:

• Observation: Patients with mild symptoms may not require specific treatment and can often be managed with observation.
• Symptomatic Relief: Over-the-counter pain relievers, such as acetaminophen or ibuprofen, can be used for abdominal discomfort.
• Increase Fluid Intake: Encouraging oral hydration to maintain fluid balance and prevent dehydration is recommended.
• Rest: Patients are usually advised to rest and avoid vigorous activities.

2. Moderate OHSS:

• Increased Monitoring: More frequent monitoring of symptoms and weight, as well as laboratory tests to assess kidney function and electrolyte levels, may be necessary.
• Symptomatic Treatment: Pain management and hydration continue, and patients may be advised to limit their physical activity.
• Ultrasound Evaluation: Repeat pelvic ultrasounds may be performed to monitor ovarian size and fluid accumulation.

3. Severe OHSS:

• Hospitalization: Patients with severe symptoms or complications may require hospitalization for close monitoring and treatment.
• Intravenous (IV) Fluids: IV fluids may be administered to manage dehydration and electrolyte imbalances.
• Electrolyte Management: Electrolytes may be monitored and replaced as necessary.
• Ascites Management: If significant abdominal fluid accumulation (ascites) is present, therapeutic paracentesis (draining fluid from the abdominal cavity) may be performed to relieve pressure and discomfort.
• Intravenous Medications: Medications to manage symptoms (such as antiemetics for nausea) may be provided.
• Supportive Care: In patients with severe OHSS, supportive care may involve monitoring for potential complications such as thrombosis or kidney failure.

4. Preventive Measures for Future Cycles:

For women who have experienced OHSS in the past or are at high risk, the following preventive measures can be taken in subsequent fertility cycles:

• Lower Gonadotropin Doses: Reducing the dosage of fertility medications can help minimize overstimulation.
• GnRH Agonist Trigger: Using a GnRH agonist instead of hCG for triggering ovulation can decrease the risk of developing OHSS.
• Coasting: Temporarily withholding gonadotropin medication before triggering ovulation to allow estrogen levels to decrease.
• Frozen Embryo Transfer: In some cases, opting for a frozen embryo transfer (rather than a fresh transfer) can allow recovery before the embryo transfer and reduce the risk of OHSS.

Conclusion

The management of OHSS involves a combination of monitoring, symptomatic relief, and supportive care. It’s essential to work closely with the healthcare provider to develop an appropriate treatment plan based on individual circumstances and the severity of the condition. If you suspect you have OHSS or are undergoing fertility treatments, maintaining open communication with your healthcare provider is crucial for ensuring your safety and well-being.