Children born after IVF treatments used for male infertility are 50 per cent more likely to suffer from an intellectual disability and are also at a higher risk of autism, a new largest-of-its-kind study has claimed.
The study led by researchers at King's College London (UK), Karolinska Institutet (Sweden) and Mount Sinai School of Medicine in New York (US) is the first to compare all available In vitro fertilisation (IVF) treatments and the risk of neurodevelopmental disorders in children.
By using anonymous data from the Swedish national registers, researchers analysed more than 2.5 million birth records from 1982 and 2007 and followed-up whether children had a clinical diagnosis of autism or intellectual disability (defined as having an IQ below 70) up until 2009.
Of the 2.5m children, 1.2 per cent (30,959) were born following IVF. Of the 6,959 diagnosed with autism, 103 were born after IVF; of the 15,830 with intellectual disability, 180 were born after IVF.
"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," said Sven Sandin, co-author of the study from King's College London's Institute of Psychiatry.
"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," Sandin said.
Developed in 1992, intracytoplasmic sperm injection (ICSI) is recommended for male infertility and is now used in about half of all IVF treatments.
Compared to spontaneous conception, children born from any IVF treatment were not at an increased risk of autism, but were at a small increased risk of intellectual disability (18 per cent increase - from 39.8 to 46.3 per 100,000 person years). However, the risk increase disappeared when multiple births were taken into account.
Children born after IVF treatments with ICSI (with either fresh or frozen embryos) were at a higher risk of intellectual disability (51 per cent increase - 62 to 93 per 100,000). This association was even higher when a preterm birth also occurred (73 per cent increase - 96 to 167 per 100,000).
Even when multiple and pre-term births were taken into account, IVF treatment with ICSI and fresh embryos was associated with an increased risk of intellectual disability (66 per cent increase for singleton birth, term birth following ICSI with fresh embryos- 48 to 76 per 100,000).
Children born after IVF with ICSI using surgically extracted sperm and fresh embryos were at an increased risk of autism but the association disappeared when multiple births were taken into account, researchers found.
The study was published in the Journal of the American Medical Association.