Children born to parents with fertility problems are more likely to develop psychiatric disorders, a large-scale population study suggests.
Dr Allan Jensen, an epidemiologist at the University of Copenhagen and co-author of this study, warned that doctors who diagnosed and treated women with fertility problems should be aware of 'the small, but potentially increased risk of psychiatric disorders among the children born to women with fertility problems'.
The researchers examined the medical records of more than 2.4 million children born in Denmark between 1969 and 2006, of whom five percent were born to women with registered fertility problems. They found that these children had a 'real but modest' increase in mental health disorders, and that this risk included both childhood as well as adult onset conditions.
According to the researchers, this figure indicates that 1.9 percent of all psychiatric disorders in Denmark are associated with a parent's fertility.
Despite the large scale of their study, the research group was unable to identify the reason for the correlation. However, they believe that any increase in risk is more likely to stem from the underlying fertility issues than IVF treatment itself.
Dr Jensen explained that 'psychiatric disorders to some degree have a genetic component' and suggested that 'damaged genes coding for psychiatric diseases are overrepresented in women with fertility problems' and could be 'transferred to their offspring'.
However, an indication of fertility problems observed in the mother's medical notes could have related to the fertility of either parent and the researchers did not look specifically at the father's health.
Dr Yacoub Khalaf, consultant gynecologist and director at the Assisted Conception Unit at Guy's and St Thomas' Hospital, was sceptical of the study findings, arguing that recent increases in the availability and effectiveness of IVF treatment should have resulted in a corresponding increase in occurrences of psychological conditions - an increase that has not been observed.
He told the Guardian, 'Surely over the years we would have seen an epidemic of mental retardation as a result of fertility treatment, which has never been observed'.
A study published last year analysing 2.5 million Swedish birth records from between 1982 and 2007 demonstrated there was no significant increase of autism in children born after IVF treatments (see BioNews 712).
Even after any possible increase, the absolute risk remains small. Susan Seenan, chief executive at Infertility Network UK, told the Scotsman that 'it is important to keep this in perspective for patients; [...] assisted conception might be the only chance they have of having a baby of their own and it is not something anyone undertakes without serious consideration of all the consequences'.
Dr Jensen added that the 'small, but potential increased risk of psychiatric disorders [...] should always be balanced against the physical and psychological benefits of a pregnancy'.