“Children born after certain infertility treatments at higher risk of autism,” reads the headline in The Independent. The news is based on a large long-term Swedish study.
Researchers looked at how children were conceived and how this might affect their risk of developing autism, a type of autistic spectrum disorder, or “mental retardation”, a term used by researchers to describe a person with an IQ under 70 (average IQ is 100).
The Independent’s headline is misleading, as the study in fact found there was no statistically significant increase in the risk of autism in children conceived through any form of in vitro fertilisation (IVF).
However, there was a statistically significant increase in the risk of mental retardation, but this increase was slight. The occurrence of mental retardation was 39.8 per 100,000 births in those conceived spontaneously, compared with 46.3 per 100,000 births in those conceived through IVF. This represents a difference of just 6.5 cases per 100,000 births.
This news should not cause alarm among those thinking about undergoing IVF treatment, but does highlight a potential association between IVF and mental development that warrants further study.
Where did the story come from?
The study was led by researchers from the Institute of Psychiatry, King’s College London and was funded by Autism Speaks, a non-profit organisation that provides funding for autism spectrum disorder research, and the Swedish Research Council. It was published in the peer-reviewed Journal of the American Medical Asssociation (JAMA).
Most of the UK media’s reporting was balanced, including The Independent’s coverage, which outlined important information on how “scientists stressed that the chances of an IVF baby being affected was tiny in real terms”. But many of the headline writers failed to make a similar distinction, with the exception of The Guardian and ITV News, which wrote that “IVF findings ‘should not stop parents using fertility treatments’.”
What kind of research was this?
This was a prospective cohort study designed to test whether the use of any IVF procedure (as well as specific types of IVF procedures) may be associated with an increased risk of autistic spectrum disorders (ASD) and mental retardation in children conceived this way. IVF allows a woman’s egg to be fertilised by sperm outside the body under controlled laboratory conditions. Different types of IVF have been developed over the years, and the researchers pointed towards previous research that suggests intracytoplasmic sperm injection (ICSI) might damage the egg when the sperm is inserted.
ICSI is usually used to treat male infertility (when the man has a low sperm count, or there are problems with the movement of sperm impeding natural conception, for instance) and involves injecting sperm directly into the egg. The research group highlight that there is little research on how IVF, and different types of IVF, influence the brain development of children conceived using these techniques. Their study aimed to fill in this gap in our knowledge.
What did the research involve?
The researchers reviewed the records of more than 2.5 million infants born in Sweden between 1982 and 2007. They recorded how they were conceived and whether they were diagnosed with ASD or had “mental retardation” at the age of four. Conception was categorised as being spontaneous (without IVF) or using IVF. The specific type of IVF used was also recorded, as was the source of the sperm (ejaculated or surgically removed).
Out of the approximately 2.5 million infants born, 30,959 (1.2%) were conceived by IVF. These were followed-up for an average of 10 years. Overall, 103 of 6,959 children (1.5%) with ASD and 180 of 15,830 (1.1%) with mental retardation were conceived by IVF.
The key results showed:
There was no statistically significant difference between the risk of the child developing ASD in those conceived spontaneously and those using IVF (all types grouped together). There was a small and borderline significant increased risk of the child developing mental retardation if they were conceived using IVF (all types grouped together) compared with spontaneous conception. The occurrence of mental retardation was 39.8 per 100,000 births in those conceived spontaneously, compared with 46.3 per 100,000 births conceived through IVF. When the analysis was restricted to single births, the increased risk of mental retardation disappeared, so it only seemed relevant to multiple births from the same mother.
Article: 12th July 2013 www.nursingtimes.net