Absolute risk is low but IVF babies 25 percent more likely to have birth defects

Infants conceived by IVF are at significantly greater risk of birth defects compared to naturally conceived babies, announced scientists at a conference last month.

'Our findings included a significant association between the use of assisted reproductive technology, such as certain types of IVF, and an increased risk of birth defects', said Dr Lorraine Kelley-Quon, a general surgery resident at the University of California Medical Center, Los Angeles, who led the research.

The study compared the incidence of birth defects in over 50,000 babies born in California, of which 4,795 were conceived by IVF and the remainder were conceived naturally. They found IVF babies were 25 percent more likely to develop defects of the heart, eyes, urinary system and reproductive organs, compared to naturally conceived infants.

However, the overall risk of birth defects is still very low, with only nine percent of babies conceived by IVF presenting with these defects. 'An estimated five million people were born using these techniques and the vast majority have no birth defects', Dr Avner Hershlag, chief of the North Shore-LIJ Center for Human Reproduction, New York, who was not involved in the study told WebMD.

The researchers also looked at infants conceived with other assisted reproductive methods, including artificial insemination and fertility-enhancing drugs. They found no statistical link between these methods and birth defects.

This is not the first investigation to identify a slight increase in birth defects following assisted fertility treatments (as reported in BioNews 395 and 485). 'We have now seen many studies from all over the world that show this association', said Dr Kelley-Quon.

However, it is still uncertain if the procedures used in fertility treatments are to blame for the increase in birth defects. A previous study in Australia (reported in BioNews 655) did not find an increased risk when using IVF, but when using ICSI where a sperm is directly injected into an egg to overcome male infertility. The authors suggested the increase in birth defects following ICSI could be due to genetic abnormalities within the sperm that cause the underlying fertility problems, not the procedure itself.

'We have to be careful about interpreting the US study because most treatments carried out there are ICSI and it seems they may have called them all IVF', Dr Allan Pacey, chair of the British Fertility Society, told the Mail Online. 'There is no convincing evidence that I know of which shows a higher risk from IVF treatment caused by the technology'.

This study, titled 'Congenital Malformations Associated With Assisted Reproductive Technology: A California State-wide Analysis', was presented at the American Academy of Paediatrics National Conference and Exhibition in New Orleans, but has not yet been peer reviewed for publication.