Risks of IVF

Many treatments also carry some health risks.

OHSS

Ovarian Hyperstimulation Syndrome (OHSS) is the most serious ‘potential’ complication that can arise from IVF treatment. The most important aspect in the management of OHSS is to try and avoid it! Women who are known to have Polycystic Ovary Syndrome (PCOS) are given a lower dose of FSH than other women, as they are more likely to over-respond to the drugs.

However, even women who do not have PCOS may over-respond to the lower dose of drugs. Monitoring of estradiol levels and vaginal scans to measure and monitor follicular growth is an important part of managing an IVF cycle, to try and give enough but not too much ovarian stimulation. If, despite these measures, there is a reasonable risk of ovarian hyperstimulation, the cycle may be stopped without Ovidrel being administered.

Without Ovidrel, OHSS can be avoided. ‘Coasting’ is an option when OHSS is a possibility. The FSH injections are stopped so that only some follicles keep developing while smaller follicles ‘die off’. When the estradiol levels drop below 10000pmol/l the trigger injection may be given and egg collection undertaken at the usual time.

Another option is to proceed with egg collection, but to freeze all the embryos instead of replacing any. This is because OHSS is more common when women become pregnant. When the ovarian stimulation uses Cetrotide or Orgalutran, there is another strategy to reduce the chance of OHSS. Ovulation can be triggered by Buserelin instead of Ovidrel – with all embryos frozen.

Signs and symptoms of OHSS are abdominal bloating and pain, often associated with nausea and diarrhoea. Increased weight, decreased urine production and shortness of breath are other symptoms. Ultrasound would show enlarged ovaries, with free fluid in the pelvic cavity and abdomen. The free fluid is called ascites. Sometimes there is fluid collection around the lungs (pleural effusion), and this causes the shortness of breath.

There are changes to the metabolism, which cause fluid to escape from the blood vessels into the body cavities, resulting in thickening of the blood and an increased risk of blood clotting. Many patients will develop mild symptoms of distension and discomfort, which can be managed with pain relief, rest and increased fluid intake at home. The clinic will monitor ovarian activity with scans, and blood tests to check blood consistency.

Daily weighing and girth measurements are also important, and an increase in these indicates increasing ascites. If nausea, pain or shortness of breath are a problem then hospitalisation will be necessary, and the patient will have intra-venous fluids (a drip) administered. ‘Heparin’ will be given to decrease the risk of clotting, and occasionally if the abdomen is very distended and uncomfortable some of the excess fluid may be withdrawn using a needle under local anaesthetic, and a drainage tube inserted into the abdomen. This will relieve the symptoms, but the fluid rapidly re-accumulates. OHSS is self-limiting, and resolves with the next menstrual period. However, it may last longer if the woman is pregnant, although usually in a less severe form than the initial symptoms.