According to a study, children born after certain IVF treatments are at a small but significant risk of developing intellectual disability.

The children born after IVF were at no greater risk for autism, researchers found in the study, which was based on data from 2.5 million children.

The study was conducted by researchers from King's College London (UK), Karolinska Institutet (Sweden) and Mount Sinai School of Medicine in New York (USA) who found that intracytoplasmic sperm injection (ICSI) for paternal infertility may be associated with higher risk of having children with intellectual disabilities.

In Intracytoplasmic sperm injection, or ICSI, a single live sperm is injected directly into the center of the human egg. The treatment is offered to couples where the male has severe infertility.

In the present study, researchers looked at data from Swedish national registers available on 2.5 births between 1982 and 2007. Researchers specifically looked at health records of children who had autism or other intellectual disability. They found that of the 6959 children with autism, 103 were born after IVF and in 15,830 intellectually disabled children, 180 were born after IVF.

When compared with natural conception, children born via IVF had a small increased risk of developing some form of intellectual disability. But the rise in risk disappeared when researchers accounted for only single births.

"IVF treatments are vastly different in terms of their complexity. When we looked at IVF treatments combined, we found there was no overall increased risk for autism, but a small increased risk of intellectual disability. When we separated the different IVF treatments, we found that 'traditional' IVF is safe, but that IVF involving ICSI, which is specifically recommended for paternal infertility is associated with an increased risk of both intellectual disability and autism in children," said Sven Sandin, co-author of the study from King's College London's Institute of Psychiatry, according to a news release. 

The study is published in the Journal of the American Medical Association.

A related study had earlier shown that children born after fertility treatments were more likely to suffer from asthma.