Women with fertility problems are significantly more likely to give birth to children who develop mental illnesses including serious psychotic conditions, a study has shown.
Whether or not the trend is linked to fertility treatment is unknown. Scientists suspect it is more likely to be the result of faulty genes that affect both fertility and mental health.
Researchers examined data on more than two million children born in Denmark between 1969 and 2006.
Of the total, five per cent were the sons and daughters of women with diagnosed fertility problems. Their risk of having any kind of psychiatric disorder was increased by a third compared with children whose mothers had no difficulty conceiving.
The chances of developing schizophrenia and other forms of psychosis was 27 per cent higher when a child’s mother had a fertility problem.
Likewise, the risk of behavioural conditions such as attention deficit hyperactivity disorder (ADHD) was raised by 40 per cent, the risk of autism and other mental development disorders by 22 per cent, and the risk of anxiety and neurotic disorders by 37 per cent.
Researchers described the higher levels of risk as “modest” but stressed that it should be balanced against the “physical and psychological benefits of pregnancy”.
Study leader Allan Jensen, from the University of Copenhagen, said the findings suggested that 1.9 per cent of all diagnosed mental illness in Denmark could be linked to mothers’ fertility.
He added: “The exact mechanisms behind the observed increase in risk are still unknown, but it is generally believed that underlying infertility has a more important role in adverse effects in the offspring than the treatment procedures.
“It is known, for example, that psychiatric disorders to some degree have a genetic component. It is perhaps thus likely that that these damaged genes coding for psychiatric diseases are overrepresented in women with fertility problems, and, if transferred to their offspring, this may at least partly explain the increased risk of psychiatric diseases.”
The findings were presented at the annual meeting of the European Society for Human Embryology and Reproduction taking place in Munich.