Experts demand cut in multiple births

Babies born as a result of in vitro fertilisation (IVF) are more at risk of complications, although this is not attributable to the technology itself, according to a Swedish study published in the Lancet last week. The increased risk of complications in IVF babies is due to the 25 times higher risk of multiple births in IVF compared to natural conception and the higher than average maternal age.

Almost half of the 5,601 babies born in the UK as a result of IVF in 1996-97 were from multiple pregnancies. The incidence of twins has almost doubled and that of triplets has trebled since the early 1980's due to the development of new infertility treatments. The Swedish researchers who compared 5,850 IVF births between 1982 and 1995 with 1.5m in the general population found that the IVF babies were more likely to be born prematurely with low birth weights and a higher rate of certain malformations. The researchers conclude that 'A high frequency of multiple births and maternal characteristics were the main factors that led to adverse outcomes, and not the in-vitro-fertilisation technique itself.' They add: 'The clinical practice of in-vitro-fertilisation needs to be changed to lower the rate of multiple pregnancy'.

In the UK, a maximum of three embryos can be transferred to a patient in one cycle of IVF. However, new guidelines to be issued next year by the Royal College of Obstetricians and Gynaecologists are likely to recommend that only two embryos be allowed per transfer. Findings of a study published in the New England Journal of Medicine last year suggested that transferring two embryos was just as effective as transferring three.