The latest figures, published today by the Human Fertilisation and Embryology Authority show that, on average, one in five treatments conducted last year ended with the birth of a baby. At the beginning of the decade the national average was 14 per cent. It is estimated that one in seven couples has problems conceiving and increasing numbers are seeking fertility treatment. Last year more than 26,685 women underwent in vitro fertilisation (IVF) treatments in clinics in Britain. These resulted in the birth of 4,138 single babies, 1,441 pairs of twins, and 176 sets of triplets.
More than a third of all women, 35 per cent, now only have two fertilised eggs implanted rather than three. Doctors used to prefer to implant more embryos to increase the chances of success but the greater risk of complications, as well as the enormous emotional and financial pressure on parents, has led to a reduction in the number used.
Advances in methods and the increasing numbers of women seeking treatments has led to the greater success of thetreatment. One of the greatest advances was the introduction in 1993 of Intra-Cytoplasmic Sperm Injection.
After initial success rates of 3.8 per cent, this now has a success rate of 20.7 per cent, and is used in over a quarter of all IVF treatments. The technique is used to alleviate low sperm counts and involves a single sperm being injected directly into an egg.
The main factors that determine success are the age of the woman, the length of time the couple have been trying to have a family and the quality of the sperm. The woman's age is one of the strongest indicators of whether or not the treatment will be successful with women aged 45 and over having only a 5 per cent chance of having a baby using IVF.
A shortage in the number of donated eggs, required when a woman's own eggs are too old or not good enough, has led to a stagnation in the number of babies born using another woman's genetic material. Last year 355 babies were born using donated eggs or embryos compared with 329 in 1998. In Britain it is illegal to pay somebody for their eggs, although egg-sharing schemes in which a woman receives free fertility treatment if she donates some of her eggs are now available in some clinics. Many couples are forced to travel to America to acquire eggs at an average cost of $10,000 (pounds 6,250).
The Patients' Guide to IVF Clinics shows for the first time success rates broken down by age. Some clinics, including St Mary's Hospital, Manchester, and University Hospital Aintree in Liverpool had no success with treating women over the age of 38 last year.