Ovarian hyperstimulation syndrome (OHSS) is a painful, serious condition that occurs when the ovaries are overstimulated due to too many fertility hormones and medications. It is generally caused by the injectable fertility medications that a woman takes during in vitro fertilisation (IVF) treatment. The purpose of these medications is to stimulate the woman’s ovaries so that more eggs are produced during normal ovulation. LH, FSH and hCG are the hormones associated with the condition.
Symptoms of OHSS can be noticed within 10 days after injectable medications have been used. If it is mild, you may experience mild abdominal pain, nausea, vomiting and sudden weight gain. If it is severe, you would experience a rapid gain in weight, shortness of breath, a tightened abdomen and severe abdominal pain and nausea accompanied by vomiting. You should contact your doctor immediately if you experience any of these symptoms.
The exact cause of OHSS isn’t known yet, but high levels of hCG contribute to the condition. HCG is given as a trigger shot, during IVF treatments so that the follicle would mature and an egg is released. When the level of hCG rises, the blood vessels in the ovaries react abnormally and fluid begins to leak which causes the ovaries to swell. It occurs within a week of receiving the injection and if you get pregnant during an IVF cycle, OHSS may worsen. This is because your body produces its own HCG, in response to your pregnancy.
These factors can increase the risk of OHSS –
– High level of estrogen before the HCG trigger shot
– Age under 30
– A large number of follicles
Some women who do not have any of these risk factors may also experience OHSS. Severe OHSS can lead to fluid getting collected in the abdomen and chest, blood clots, ovary getting twisted, cyst getting ruptured, a miscarriage and in rare cases, death.
OHSS can be prevented with the help of a plan customised by your doctors. The lowest possible dose of gonadotropins should be given by the doctor, in order to stimulate the ovaries and trigger ovulation. If you have a huge number of follicles or the level of oestrogen in your body is high, the doctor may stop injectable medication and wait for a few days before the HCG is administered. If you have OHSS, it most likely would go away on its own but you would be monitored by your doctor closely, especially fluid retention and swelling around the abdomen and legs.
OHSS often develops after the HCG shot, which is why alternatives to HCG are used nowadays, to prevent the condition. Gn-RH agonists are used as an alternative. During IVF, the follicles may be removed from the ovaries. These follicles are then fertilised and frozen and the ovaries can rest. This could reduce the risk of OHSS. Once your body is ready, the IVF process can be resumed.