IVF and mental retardation, autism risk – experts respond

IVF_embryosA Swedish study has found that IVF treatment is not associated with increased risk of developing an autistic disorder, however it was associated with a small but statistically significantly increased risk of mental retardation.

The authors note that the prevalence of these disorders was low, and the increase in absolute risk associated with IVF was small. When the study was restricted to singletons (single births), the risk for mental retardation was no longer statistically significant.

The study also examined the risks associated with specific IVF procedures including intracytoplasmic sperm injection (ICSI) for male infertility and whether embryos were fresh or frozen. IVF with ICSI for male infertility was associated with a small increase in the risk for autistic disorder and mental retardation compared with IVF without ICSI.

The comments below were gathered by our colleagues at the UK and AusSMCs. Contact us for help finding a local expert on this topic.

Dr Allan Pacey, Fertility Expert at the University of Sheffield and Chairman of the British Fertility Society, said:

“This is a very important study which defines the risks of IVF children being born with two neurodevelopmental disorders. It is a large study and is exactly the kind we need if we are to give patients accurate information before they embark on treatment.

“The main message of the paper is a positive one, suggesting that any risk of these disorders is very low, or absent, in comparison to children conceived naturally. However it does highlight the importance of preferentially using standard IVF rather than ICSI, and also using ejaculated sperm rather than those recovered surgically from the testicle, in situations where it is possible to do so.

“Patients about to embark on treatment should not worry and should discuss any concerns about their treatment plan with the team responsible for their care.”

Professor Paul Colditz, Professor of Perinatal Medicine and Director of the Perinatal Research Centre at the University of Queensland, said:

“This study provides further strong broad evidence that babies born after IVF are healthy. In a large cohort in Sweden, they found that, compared with spontaneous conception, 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.

“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. In the Swedish cohort, single-embryo transfers increased from 10% to 70% and the rate of preterm births dropped from 40% to 10% across the study period. However, at the end of the period, the preterm birth rate was still twice that of spontaneous conceptions.

“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.”

Dr Dagan Wells, Institute of Reproductive Sciences, Nuffield Department of Obstetrics and Gynaecology, University of Oxford, said:

“In general the results of the study should be reassuring for patients undergoing IVF treatment. They show that risks of problems such as autism and mental retardation remain low following infertility treatments.

“However, the research does suggest that patients having certain types of procedure, specifically those receiving treatment for severe male infertility, may see a small increase in the occurrence of autism. It is not clear whether the slightly elevated risk is somehow related to the father’s infertility or whether it is caused by the treatment process itself.

“Assessing the long-term effects of treatments such as IVF is difficult. Technologies are constantly evolving and changing, presenting a moving target for doctors and scientists. A limitation of this study is that some of the data comes from treatments carried out 30 years ago, when IVF was in its infancy. The methods used today differ significantly from techniques used decades ago. Whether they are more or less safe remains to be seen.

“The use of IVF is growing and now accounts for between 1% and 5% of all births in most industrialised countries. Consequently, an improved understanding of any associated problems is of great importance. So far, multiple studies evaluating children born after IVF have indicated that it is a safe procedure- any increases in the risk of medical problems appear to be small. However, there is still very little information about the long-term health of the children born. More studies of this type are needed.”

Associate Professor David Amor is Director of Victorian Clinical Genetics Services at Murdoch Childrens Research Institute, said:

 “Although IVF is generally considered to be safe, conception by IVF is known to carry an increased risk of congenital abnormalities in the child. In absolute terms, congenital abnormalities are present in about 4 out of every 100 IVF conceived children, compared with 3 out of every 100 naturally conceived children. The reasons for this increased risk for IVF conceived children are not well understood, but 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 examines whether children conceived using IVF might also be at increased risk of autism and intellectual disability. Overall, the study is reassuring, and 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 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.”