The rest of the world has been urged to follow Australia and New Zealand's IVF policy of transferring one embryo to achieve a pregnancy, which has been shown to reduce stillbirths and early infant mortality.
A study of 50,000 Australian IVF births between 2004 and 2008 showed a significantly higher infant mortality rate following the transfer of two embryos rather than one.
The risk of a 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.
The University of New South Wales (UNSW) study showed twins accounted for a third of all perinatal deaths and half of stillbirths.
Twins also had a higher mortality rate than children from single births.
The voluntary single embryo transfer policy in Australia and New Zealand had led to a reduction in overall perinatal mortality for babies conceived using IVF and ICSI (intracytoplasmic sperm injection).
Single embryo transfers rose from 14 per cent in 1999 to 68 per cent in 2008 in Australia and New Zealand IVF cycles.
At the same time multiple births dropped from 22 per cent to eight per cent.
UNSW Professor Michael Chapman said multiple pregnancies carried a higher risk of complications and maternal and infant mortality than single pregnancies.
"The biggest downside of IVF is probably multiple pregnancy," he told AAP from an international fertility conference in Istanbul, where the research was presented on Wednesday.
Prof Chapman said the policy should be adopted globally because it reduced the rate of multiple pregnancies and "babies born from single embryos are better babies".
Only about 24 per cent of IVF/ICSI cycles in Europe involved single embryo transfers in 2009, while more than half were double embryo transfers, according to the European Society of Human Reproduction and Embryology, which is hosting the conference.
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