Like any medical and surgical treatment, assisted conception is associated with some degree of risk. Every effort is made to minimise the likelihood of any such risk, although it is important to highlight those most commonly quoted.
Current national statistics indicated that 1 in 4 of all assisted conception pregnancies result in multiple births.Each clinic now has a strategy for reducing the number of multiple births. Having a multiple pregnancy should not be underestimated. The risks to the woman and fetus include an increased risk of miscarriage, an increased risk of complications such as raised blood pressure, and a higher chance of delivering prematurely.
The risk of multiple pregnancy can be removed by transferring only one embryo in IVF treatment.
Ovarian hyper stimulation syndrome (OHSS)
Despite careful monitoring some women respond excessively to stimulation of the ovaries resulting in the development of a large number of follicles/ eggs, causing the ovaries to swell. This is known as ovarian hyper stimulation syndrome. It is estimated that 7% of those receiving stimulatory drugs in IVF treatment experience mild symptoms, and 1% experience severe hyper stimulation requiring intravenous fluid treatment.
Occasionally an IVF treatment may be cancelled to prevent OHSS, or the treatment may be ‘coasted’, that is, waiting a couple of days for the risk time to pass and then completing the IVF cycle. This is not always possible.
Sometimes the ovaries respond inadequately to the drugs and none, or very few, eggs develop. If it seems unlikely that we will collect many eggs, and therefore the chances of conceiving in a particular cycle are poor, we may advise that the treatment cycle is cancelled.