CHILDREN conceived through a common method of IVF are more likely to suffer birth defects, a major study suggests.
Research on more than 300,000 babies found those born following a fertility treatment used when men have low sperm counts had a higher risk of abnormalities than those conceived naturally. Babies born as a result of intracytoplasmic sperm injection (ICSI) — where a sperm is injected into the egg — were more likely to suffer abnormalities.
Researchers were unable to establish if this was because the technique itself increases the risks of abnormality or because men suffering from sperm damage were more likely to pass on anomalies.
The method is used in around half of fertility treatments in the UK. The study also found traditional IVF did not significantly increase the risk of defects. In traditional IVF, sperm and eggs are mixed in a dish and sperm breaks into the egg on its own.
The research, led by the Robson Institute at the University of Adelaide and published in The New England Journal of Medicine, examined 309,000 births in South Australia. Of these, 1,878 involved ICSI.
The study found the risk of a birth defect was 5.8 per cent following natural conception, compared with 7.2 per cent following conventional IVF, and 9.9 per cent after ICSI.
Since its introduction in 1992, increasing numbers of fertility clinics have adopted ICSI as their procedure of choice.
Dr Allan Pacey, fertility expert at the University of Sheffield and chairman of the British Fertility Society, said: "The study suggests that while babies born from IVF are as healthy as their naturally conceived counterparts, there is still some residual risk to babies born through ICSI that currently cannot be explained."
He said previous research had established that babies conceived naturally to couples previously diagnosed with infertility were at higher risk of abnormalities, suggesting that birth defects were more likely to be linked with "infertility" than with the "technology" used to overcome it.
Professor Peter Illingworth, an associate professor at the University of Sydney, said: "It may well be that the families who have to use ICSI have extreme sperm damage, and this may be why there is a higher rate of anomalies in this group."