USING only one embryo during IVF reduces the risk of stillbirths and early infant mortality, a groundbreaking Australian study reveals.
The study of 50,258 Australian and New Zealand IVF births between 2004 and 2008 revealed a single embryo transfer (SET) significantly reduced the infant mortality rate, as opposed to when two embryos were used.
The risk of stillbirth or an infant dying in the weeks immediately after birth following a double embryo transfer was 53 per cent higher than with babies born after one embryo was implanted.
Professor Elizabeth Sullivan from NSW University's perinatal and reproductive epidemiology research unit presented the research at the European Society of Human Reproduction and Embryology conference in Istanbul yesterday.
"The number of embryos transferred per procedure is the major determinant of multiple pregnancy and multiple delivery, which contribute to an elevated risk of preterm birth and low birth weight," Professor Sullivan said.
"Australia and New Zealand have shown that in the right policy environment a voluntary change to SET practice is achievable," she said.
Single embryo transfers rose from 14 per cent in 1999 to 68 per cent in 2008 in Australia and New Zealand IVF cycles compared with about 20 per cent in Europe. At the same time multiple births dropped from 22 per cent to 8 per cent.
Genea fertility clinic began the single embryo transfer trend more than 10 years ago. Only about 5 per cent of women having babies through Genea have multiple births.
Genea's medical director Associate Professor Mark Bowman said single embryo transfers gave parents a higher chance of getting a healthy baby: "The single embryo transfer means fewer twins, which means more healthy babies without it lowering the chances of the IVF working."