success rates

How great are the chances of success?

In an IVF treatment, the chance of pregnancy per cycle is around 20% on average. However, this is highly dependent on individual circumstances such as age, sperm quality and the number and quality of the embryos. In addition, not all pregnancies lead to a live-born child. A quarter of all pregnancies begun end in a miscarriage (20% of the total) or in an ectopic pregnancy (5%).

Because there are new chances with every cycle, half the couples on average return home with one child or more after three attempts.

IVF results can be displayed in various ways. The following definitions have been used:

• Started cycle  IVF attempt, from the start of the drugs to stimulate follicle growth.
• Follicle puncture  Ovary puncture with the aim of obtaining egg cells.
• Embryo transfer: Placing of embryos in the uterine cavity.
• Pregnancy: Positive test in urine or serum (>50 IE/L), no earlier than 15 days after the puncture. 
• On-going pregnancy: intact intra-uterine pregnancy, > 10 weeks after the puncture.
• Confidence interval: interval in which there is a 95% certainty.

The number of continuing pregnancies per cycle started has been chosen as the method of recording and comparing the IVF figures. This percentage tells us something about the care delivered by a centre – but is far from the whole story.

• Firstly, this percentage is dependent on all sorts of other factors, such as the age of the woman, the length of time she has wanted a child and the number of previous treatments. These factors may vary from centre to centre. For example, if a centre primarily treats older women, that centre’s chances of a pregnancy will be lower.
• Secondly, this percentage may vary from year to year for unpredictable causes. It therefore makes sense to look at the results over several years.
• Finally, other factors such as patient satisfaction, the percentage of complications and the percentage of multiple births are also important to the quality of care. If several embryos are transferred, for example, not only do the chances of a pregnancy increase, but so also do the chances of multiple births with all the associated risks.

All in all then, you have to be careful when interpreting these figures.