Ovarian hyperstimulation syndrome

It’s normal for the ovary to produce fluid in the abdomen as a follicle grows, and to bleed at ovulation. And it’s normal for a corpus luteum to form in the ovary and become cystic in the second half of the cycle. Pain can accompany ovulation and the formation of the corpus luteum, while premenstrual tension can cause bloating, irritability, depression and breast pain. When the ovaries are stimulated to increase the numbers of follicles, as occurs in IVF, all these events and their symptoms can be more pronounced than you might expect in a natural cycle.

Our years of experience at Hollywood Fertility Centre indicate that 1 in 30 stimulations is accompanied by enough pelvic pain in the luteal phase to cause a woman to want to rest in bed for a day or two (mild OHSS).

In about 1 in 250 stimulations, a hospital rest results, mainly for observation and to enable us to give adequate relief of pain (moderate OHSS).

In about 1 in 1000 stimulations however, there’s enough fluid in either the abdomen or the chest to be of serious medical concern. Severe OHSS increases a woman’s chance of developing a blood clot, which is potentially life threatening. Signs to watch out for are vomiting, diarrhoea and shortness of breath. Contact the Hollywood Fertility Centre if you experience any of these symptoms.

OHSS is a self-limited condition and the ovaries will almost always completely recover. The signs and symptoms will get worse before they get better if there has been a successful conception, because the natural production of human chorionic gonadotrophin (hCG) will then be added to the injected hCG and keep the ovaries stimulated and enlarged for an extra few weeks.

Rarely (in about 1 in 5,000 cases of OHSS), an enlarged ovary can twist on itself, cutting off its blood supply and causing excruciating pain that necessitates immediate hospital admission.

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