Ovarian hyperstimulation: a complication we now know how to prevent

Ovarian hyperstimulation syndrome occurs when the ovaries react excessively to stimulation: they enlarge, fluid leaks from the blood vessels into the abdomen, and the blood becomes concentrated. In its mild form, it still affects a significant proportion of cycles. In its severe form, it has become rare — less than 1 per cent — thanks to modern protocols.

Who is at risk

• Polycystic ovary syndrome, or simply a high AMH level, above 3.5 ng/ml.
• A high antral follicle count, above approximately 20.
• Young age and a low body mass index.
• A history of hyperstimulation during a previous cycle.
• A strong response during the cycle: more than 18 to 20 follicles, very high oestradiol levels.

If any of these apply to you, please tell your doctor before the treatment begins, even if your medical records already mention them. The article on PCOS provides further details on this profile.

How to avoid it

Three measures have transformed the situation:

The antagonist protocol, which allows hCG triggering to be replaced at the last minute. Triggering using a GnRH agonist instead of hCG: this is the most effective measure, as it eliminates the factor that perpetuates the syndrome. The freezing of all embryos, known as the ‘freeze-all’ approach, with transfer during a subsequent cycle: an ongoing pregnancy produces hCG and can trigger a late-onset, more severe form of the syndrome. Freezing the embryos prevents this entirely.

In addition, there are cautious initial doses, close ultrasound monitoring, and sometimes treatment with cabergoline. Some clinics still recommend abandoning the cycle in the event of an extreme response, which remains a legitimate option.

Recognising the signs

Abdominal discomfort and mild bloating in the days following egg retrieval are common. What is not normal:

• Rapid weight gain, of more than one kilo per day, or more than three kilos in total.
• A tight and painful abdomen, with a visibly increasing waist circumference.
• Persistent vomiting, inability to drink.
• A marked reduction in urine output, or very dark urine.
• Shortness of breath or difficulty breathing whilst lying down.
• Pain or swelling in a calf, suggesting a blood clot.

These signs require you to call the clinic on the same day, and the last three require you to go to A&E immediately.

What to do in the meantime

Drink fluids rich in electrolytes rather than water alone, around one to two litres a day; weigh yourself every morning; note your urine output; stay active to prevent blood clots whilst avoiding strenuous exercise; and avoid anti-inflammatory drugs. Mild cases resolve on their own within one to two weeks if pregnancy has not occurred.

The critical point when receiving treatment abroad

You will return to France in the days following the egg retrieval, yet the late-onset form typically appears precisely between the fifth and twelfth day. Three precautions that I always put in place: take a copy of the cycle report in French with you, stating the number of follicles retrieved and the method of ovulation induction, to present to A&E if necessary; have the direct contact number for the Greek clinic and my own, both of which must be reachable; and know from the outset which department to contact near your home. A French A&E doctor who admits a patient with abdominal distension without any context wastes precious time; the same doctor, with the report, understands the situation immediately.

Finally, please note that with a frozen embryo transfer cycle or the receipt of donor eggs, you do not undergo any ovarian stimulation: this risk does not apply to you at all.

Frequently asked questions

Source: https://fertilitegrece.com/en/blog/ovarian-hyperstimulation-syndrome/ — Triada Baloukoudis, IVF patient coordination in Greece. General information, not medical or legal advice. Printed on