Ovarian Hyperstimulation Syndrome (OHSS)

Ovarian hyperstimulation syndrome (OHSS) is a condition where the ovaries react abnormally to drugs administered for inducing conception. It is characterized by significant ovarian enlargement due to multiple ovarian cysts, and a fluid shift in the tissue space. While most cases of OHSS are mild, severe cases do occur, although they’re rare.

What Is Ovarian Hyperstimulation Syndrome (OHSS)?

OHSS majorly affects women undergoing fertilization induction treatments and taking hormonal preparatory injections and drugs to promote the growth of eggs in the ovaries.

An excess dose of hormonal remedies or hormone-mimicking drugs can lead to OHSS, in which the ovaries become enlarged and are painful. It is usually mild or moderate, but a few women may have a severe form of this condition, which may lead to excess weight gain, pain in the stomach, vomiting and breathing difficulties.

Spontaneous ovarian hyperstimulation syndrome is not related to fertility treatments and is rare.

Who Is At Greater Risk Of Developing OHSS?

The following factors have been linked to an increased prevalence of ovarian hyperstimulation syndrome or OHSS:

• Young age: Young women in the reproductive age group, usually under 35 years of age
• Polycystic Ovarian Syndrome or PCOS: Women who suffer from or have a history of PCOS, a condition of young women wherein the ovary is filled with small cysts and cause menstrual irregularities
• Assisted Reproductive Techniques (ART): Women undergoing treatments for either primary or secondary infertility with techniques like IVF, IUI or OI. ART is the most common cause found to be associated in most of the cases diagnosed with OHSS
• A previous history of OHSS increases the OHSS risk

Causes

Human Chorionic Gonadotropin (hCG) is a hormone normally produced and responsible for fertilization. It is medically supplemented in deficient women, and it is this hormone that may cause OHSS if present in excess amounts. OHSS occurs only after the eggs are released from the ovary (ovulation).

• Injectable Hormonal medications: After a dose of human chorionic gonadotropin (hCG), the patient may develop symptoms of OHSS.
• Repeated or high doses of ovarian stimulators: Patients who get more than one dose of hCG after ovulation may develop OHSS.
• Pregnancy: If a woman becomes pregnant (as a result of her normal ovulation) during this cycle of treatment, the externally administered hormone may overstimulate the ovary and cause OHSS.

About 3 to 6% of women who undergo IVF develop OHSS after embryo transfer as a complication of treatment.

Symptoms

OHSS usually develops about 10 days after fertility treatments.

Symptoms of mild to moderate OHSS

• Mild pain in the tummy
• Bloating of abdomen
• Vomiting
• Loose motions
• Pain on touching the lower abdomen around the ovaries
• Drastic weight gain of about 3 kgs

Symptoms of Severe OHSS

• Rapid weight gain – 15 kgs in about 10 days
• Severe abdominal pain
• Severe gastric upset including vomiting and nausea
• Increased viscosity of blood in the lower limbs
• Reduced urine output
• Breathing difficulties
• Tense, distended abdomen

Complications

Usually, OHSS risk is mild to moderate. But about 1 in 100 women undergoing stimulation of ovaries develop a severe grade of OHSS.

• Hemodynamic and electrolyte disturbances: Drastic fluid shifts out of the blood vessels may affect the blood pressure and salts of the body (sodium, potassium, etc.)
• Thrombotic states: As oestrogen is a pro-coagulant hormone, one may develop hemoconcentration (excessively thick and viscous blood) and hence abnormal blood clots in large vessels, usually in the lower limbs
• Acute kidney failure
• Twisting of the ovary (ovarian torsion)
• Rupture of a cyst (fluid or blood-filled cavity) in an ovary, which can lead to serious bleeding
• Excess fluid causes shortness of breath
• Miscarriages or abortions
• Death (OHSS may be fatal in severe cases)

Diagnosis

OHSS is based on a combined approach with clinical examination and tests including blood tests and sonography. Abnormal weight gain, increased waist circumference, attributes like abdominal pain, breathing difficulties or urinary complaints may alert your doctor to investigate you for OHSS.

You may need a vaginal ultrasound, which shows enlarged ovaries usually containing fluid-filled cysts. A very high beta hCG level or deranged kidney function tests may hint towards a diagnosis of OHSS.

Treatment

Mild OHSS usually resolves spontaneously in about a week’s time after diagnosis. You may require an OHSS diet. Eating a high-protein diet is recommended. Please consult your doctor before starting any new diet.

Moderate OHSS requires close monitoring of vital parameters. Adequate fluids prevent dehydration.

Severe OHSS usually necessitates hospitalization and aggressive treatment, including IV fluids, anticoagulants (blood thinners), electrolyte corrections, blood components and intensive care including cardiovascular backup and OHSS radiology management.

Are There Any Home Remedies To Cure Ovarian Hyperstimulation Syndrome (OHSS)?

There are no scientifically documented home remedies for the treatment of OHSS. It is recommended to refrain from drinking excessive amounts of water or consuming any anti-inflammatory medicines such as aspirin as this can affect your kidneys. Also ensure to keep moving your legs periodically to lower the risk of blood clots.

Prevention

Certain medical measures help prevent OHSS.

Reducing excessive gonadotropins: Low dose gonadotropin protocols have been publicized to prevent OHSS in high-risk patients with a past history or PCOS. It includes various steps like:

• Cycle cancellation (withholding hCG)
• Coasting or Soft landing (in case you have high oestrogen levels or many developed follicles, your doctor may recommend waiting for a few days before administering hCG, which triggers ovulation)
• Modification of ovulation-triggering agent: Replacement of hCG by exogenous or endogenous LH (central hormone controlling the activity of ovaries)

When to call a Doctor?

It is advisable to consult your gynecologist as soon as you notice any abnormal symptoms, abdominal or urinary, or a general sense of being unwell.

Conclusion: Since OHSS is usually a side effect or complication of fertility treatment, it should have a high index of suspicion by the treating gynecologist. It may be prevented if diagnosed in the early stages. Consult your doctor if you suspect any symptoms. OHSS can be treated effectively with an integrated approach of a gynecologist, a physician, and an intensivist (critical care physician).