Australasian Science: Australia's authority on science since 1938

IVF Increases the Risk of Mental Retardation

A Swedish study has found that IVF was associated with a small risk of mental retardation.

“This study provides further strong broad evidence that babies born after IVF are healthy. IVF treatment was not associated with autistic disorder in the offspring but was associated with a small but statistically significantly increased risk of mental retardation. This, however, disappeared when the analysis was restricted to singletons (single births).

The two endpoints of autism and mental retardation were chosen because of their major adverse effects on children’s development, but each is relatively uncommon. Much more common are neurodevelopmental trajectories that result in poor school achievement. Several large studies in a number of countries have shown that prematurity is a major determinant of poor school achievement.

In the Swedish IVF cohort, the rates of prematurity were 2–4 times greater than in the spontaneously conceived group. This is substantially attributable to the fact that multiple birth was 8–14 times higher in the IVF group. The rates of multiple birth and prematurity are falling as IVF technology advances.

The paper has established that the two major adverse neuro­developmental outcomes measured are either not increased or, at worst, only very slightly increased in children born through IVF. The question of whether IVF contributes to other more common but more subtle adverse neurodevelopmental outcomes remains unanswered.”

Prof Paul Colditz is Professor of Perinatal Medicine and Director of the Perinatal Research Centre at the University of Queensland.

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“This study is largely reassuring for parents of IVF babies with respect to autism and mental retardation in their child. It emphasises facts that are known already about the risks for multiple pregnancies and those conceived by sperm injection (ICSI).

Australia has led the way in reducing multiple pregnancies by promoting the transfer of only one embryo, but the use of ICSI is increasing... It is unclear whether the ICSI risks are a result of genetic factors from the parents, or the actual procedure of sperm selection by the embryologist.”

Prof Robert Norman is Professor of Reproductive and Periconceptual Medicine and Director of the Robinson Institute at The University of Adelaide.

“Although IVF is generally considered to be safe, conception by IVF is known to carry an increased risk of congenital abnormalities in the child. The reasons for this increased risk for IVF conceived children ... appear to include a mixture of risks associated with the IVF procedure itself, and risks associated with predisposing factors already present in the infertile couple.

This large study from Sweden ... does not indicate an increased risk of autism and intellectual disability in most typical IVF settings. However, there is a suggestion that the risk of autism and intellectual disability might be increased in certain situations, especially for males that have very low sperm counts, which require sperm to be extracted surgically from the testes. There also seem to be increased risks associated with multiple births and premature births, which are known to occur more commonly in IVF pregnancies.

Overall this paper is consistent with previous data from Australian and international studies that suggest that IVF conception does carry an increased risk of health problems in the child, but that this increase in risk is very small and is unlikely to deter most infertile couples from using IVF.”

A/Prof David Amor is Director of Victorian Clinical Genetics Services at the Murdoch Children’s Research Institute.

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“Traditionally, in vitro fertilisation (IVF) has been used to address fertility issues. However, where there are problems with the sperm, IVF isn’t enough. Another technique called intracytoplasmic sperm injection (ICSI) was developed where the sperm are injected straight into the female’s egg. Concerns have been raised about this technique as it bypasses the ‘natural selection’ of the best sperm for fertilisation. Additionally, assisted reproduction procedures have been associated with a number of serious disorders.

This study has surveyed a large number of births resulting from either natural conception or assisted reproduction. Overall, any type of assisted reproduction (IVF or ICSI) was associated with an increase in mental retardation.

Although the results of these studies show only a small increase in the risk of developing neurological disorders, they are significant as ICSI is now overtaking conventional IVF procedures. With this increase in the use of ICSI it may be expected that a rise in autistic disorder and mental retardation may be observed in Australian children. However, importantly for couples in Australia, the emphasis is on replacing only one embryo into the woman resulting in a single pregnancy and, hopefully, avoiding the neurological disorders observed in this study.”

Dr Jemma Evans is a Senior Research Officer at Prince Henry Institute in Melbourne

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“Earlier small studies reported similar associations as this much larger study. Although the overall correlations were significant, the absolute impact remained low because of the limitations of statistical procedures used. Thus, this study calls for caution, not alarm.

It would be significant if some of the spare embryos from these couples were donated for research. They could be used to produce helpful cell types, like neurons, to understand and validate molecular mechanisms – for example, the role of epigenetics in disease development, if any.”

A/Prof Kuldip Sidhu is an expert in Regenerative Medicine at the Centre for Healthy Brain Ageing at the University of New South Wales.

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