Assisted Reproduction: the Risks

A study finds that assisted reproduction raises the possibility of birth defects, but these vary with the methods used

A University of Adelaide study has identified various risks of major birth defects associated with different types of assisted reproductive technology. According to a university release, ‘researchers from the University’s Robinson Institute have compared the risk of major birth defects for each of the reproductive therapies commonly available internationally, such as: IVF (in vitro fertilisation), ICSI (intracytoplasmic sperm injection) and ovulation induction. They also compared the risk of birth defects after fresh and frozen embryo transfer. The results have been published in New England Journal of Medicine’.

‘Researchers linked a census of more than 6,100 assisted reproductive technology births in South Australia to a registry of more than 300,000 births and 18,000 birth defects. They compared risks of birth defects across all infertility treatments to pregnancies in women with no record of infertility. They also compared successive pregnancies for women’.

“The unadjusted risk of any birth defect in pregnancies involving assisted conception was 8.3 per cent (513 defects), compared with 5.8 per cent for pregnancies not involving assisted conception (17,546 defects),” lead author Michael Davies says.

“The risk of birth defects for IVF was 7.2 per cent (165 birth defects); and the rate for ICSI was higher at 9.9 per cent (139 defects).”

“A history of infertility, either with or without assisted conception, was also significantly associated with birth defects. While factors associated with the causes of infertility explained the excess risk associated with IVF, the increased risk for a number of other treatments could not readily be explained by patient factors. ICSI, for instance, had a 57 per cent increase in the odds of major defect, although the absolute size of the risk remained relatively small.”

Davies says cryopreservation (freezing) of embryos was associated with a substantially reduced risk of birth defects, particularly for ICSI. “This may be due to developmentally compromised embryos failing to survive the freeze/thaw process,” he says.

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