A woman's risk of having a baby with birth defects increases with her age. Babies born to women aged 40 and over from assisted reproduction technologies are likely to have fewer birth defects compared with those from women who conceive naturally at the same age, new research has found.
"There's something quite remarkable occurring with women over the age of 40 who use assisted reproduction," said lead author Michael Davies, Professor at Robinson Research Institute, University of Adelaide in Australia.
‘Babies born to women aged 40 and over from assisted reproduction technologies are likely to have fewer birth defects compared with those from women who conceive naturally at the same age.’
"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," Davies noted.
The researchers believe this could point to the presence of more favorable biological conditions in IVF (in vitro fertilization) specific to pregnancies in older women.
Published in the BJOG: An International Journal of Obstetrics & Gynecology (BJOG)
, the research is based on data of all live births recorded in South Australia from 1986-2002.
These include more than 301,000 naturally conceived births, as well as 2,200 births from IVF and almost 1,400 from ICSI (intracytoplasmic sperm injection).
The average prevalence of a birth defect was 5.7% among naturally conceived births, 7.1% for the IVF births, and 9.9% for the ICSI births, across all age groups.
In births from assisted reproduction, the prevalence of birth defects was 3.6% for women aged 40 and older using IVF.
For natural conceptions, the corresponding prevalence was 8.2% in women aged 40 plus.
"For women treated with IVF and ICSI combined, the greatest age-related risk of birth defects was among the young women, at or around 29 years of age," Davies said.
"With a prevalence of 9.4%, their risk was more than double the rate of 3.6% observed for the patients aged over 40, and significantly higher than for fertile women of the same age, at 5.6%," Davies noted.