Children born to obese women with diabetes are over four times as likely to be diagnosed with autism spectrum disorder than those born to healthy mothers, a new study has warned.
Autism spectrum disorder is a neurodevelopmental condition characterised by severe deficits in socialisation, verbal and nonverbal communication and repetitive behaviours.
Researchers from Johns Hopkins Bloomberg School of Public Health in US analysed 2,734 mother-child pairs.
They collected data on maternal pre-pregnancy weight and whether the mothers had diabetes before getting pregnant or whether they developed gestational diabetes during pregnancy.
They also followed up the children from birth through childhood via postnatal study visits and review of electronic medical records.
Researchers identified 102 children who were diagnosed with autism spectrum disorder over the course of the study.
Those children with mothers who were both diabetic and obese were more than four times as likely to develop autism compared to children born to normal weight mothers without diabetes, they found.
"Our research highlights that the risk for autism begins in utero," said M Daniele Fallin from the Bloomberg School's Department of Mental Health.
"It is important for us to now try to figure out what is it about the combination of obesity and diabetes that is potentially contributing to sub-optimal foetal health," Fallin said.
Along with pre-conception diabetes, children of obese mothers who developed gestational diabetes during pregnancy were also at a significantly higher risk of being diagnosed with autism.
Previous studies had suggested a link between maternal diabetes and autism, but this is believed to be the first to look at obesity and diabetes in tandem as potential risk factors.
The findings highlight a leading theory about autism, that the risk likely develops before the child is even born.
The biology of why obesity and diabetes may contribute to autism risk is not well understood. Obesity and diabetes in general cause stress on the human body, researchers said.
Previous research suggests maternal obesity may be associated with an inflammation in the developing foetal brain.
Other studies suggest obese women have less folate, a B-vitamin vital for human development and health.
The findings were published in the journal Pediatrics.
