July 3, 2013
Some IVF Treatments My Raise Risk Of Intellectual Disabilities
Brett Smith for redOrbit.com - Your Universe Online
A study on in vitro fertilization (IVF), which included more than 2.5 million births, found certain treatments are associated with a small but statistically significant increase in risk of mental retardation.
According to a study, which was published recently in the Journal of the American Medical Association, the prevalence of the developmental disorder was still relatively low and the amount of increased risk was small.
The study included anonymous data from 1982 to 2007 on over 2.5 million births taken from national registers in Sweden. The birth data was followed-up with a determination of whether these children had been diagnosed with autism or intellectual disability up until 2009.
The researchers found 1.2 percent of the child births were the result of IVF. Autism was diagnosed in 1.5 percent of children and mental retardation in 1.1 percent of the children who were born via IVF.
The study included all six different types of IVF procedures available in Sweden - including those that inject a single sperm directly into an egg, known as intracytoplasmic sperm injection (ICSI). They also considered whether the IVF procedure used fresh or frozen embryos and whether sperm was ejaculated or surgically extracted.
"IVF treatments are vastly different in terms of their complexity," said co-author Sven Sandin, from King's College London's Institute of Psychiatry. "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," he noted.
Children of IVF births that included ICSI were at a 51 percent increased risk of intellectual disability. The level of increased risk was even greater in the cases of preterm birth, a 73 percent increase. When researchers considered multiple and pre-term births, IVF treatment with ICSI and fresh embryos was linked to a 66 percent increased risk of intellectual disability for full-term, single birth.
"Our study shows that treatments developed to manage male infertility are associated with an increased risk for developmental disorders in the offspring," said co-author Dr. Avi Reichenberg, a professor of psychiatry and preventative medicine from King's College London and Mount Sinai School of Medicine. "The exact mechanism is unclear, but there are a number of risk factors, from selection of IVF procedures, to multiple embryos, and to preterm birth.
"Whilst intellectual disability or autism remain a rare outcome for IVF, being aware of the increased risk associated with specific types of IVF means offspring at risk can be identified and potentially monitored for developmental disorders, ensuring they receive early detection and appropriate support and care," Reichenberg added.
"It's important to remember that the majority of children are born perfectly healthy following IVF," said co-author Dr. Karl-Gosta Nygren, a professor of Obstetrics and Gynecology from Karolinska Institutet. "Our study provides much needed information for parents and clinicians on the relative risks of modern IVF treatments, enabling them to make the most informed choice possible.
"Our study also provides further evidence for the need to minimize multiple embryo transfer. However, more research is needed to elucidate the reasons behind our findings," Nygren concluded.