WOMAN who are over 40 may have healthier babies if they use IVF rather than natural conception, according to new research.
The findings fly in the face of traditional attitudes that the risks of IVF causing birth defects increase as the mother ages.
But a University of Adelaide study finds the age for the highest risk of birth defects is at 29 for mums who use IVF.
The results have been published in BJOG: An International Journal of Obstetrics and Gynaecology.
Lead researcher Adelaide University's Professor Michael Davies said there was "something quite remarkable" occurring with women over 40 using IVF.
He said women using IVF have been shown to have a higher risk of birth defects compared to women who conceive naturally.
And that women who conceive naturally have a higher risk of defects beyond age 35.
"Therefore, it was widely assumed, but untested, that maternal age would be a key factor in birth defects from assisted reproduction," he said.
"However, our findings challenge that assertion.
"They show that infertile women aged 40 and over who used assisted reproduction had less than half the rate of birth defects of fertile women of the same age, while younger women appear to be at an elevated risk."
The research is based on data of all live births recorded in South Australia between 1986 and 2002, more than 301,000 natural-conceived babies plus 2200 births from IVF from ICSI, another form of assisted reproduction.