Inducing labour may raise the risk of autism US study finds Smaller studies suggested a possible tie between induced labour and autism, but the new research is the largest to date, involving more than 600,000 births. The researchers examined eight years of North Carolina birth records, and matched 625,042 births with public school data from the late 1990s through 2008. Information on autism diagnoses didn't specify whether cases were mild or severe. Labor was induced or hastened in more than 170,000 births. Overall, 5,648 children developed autism - three times as many boys as girls. Among autistic boys, almost one-third of the mothers had labour started or hastened, versus almost 29 per cent of the boys without autism. The differences were less pronounced among girls. Oxytocin and prostaglandins are used to start or speed up labour but the study doesn't identify specific medications. The strongest risks were in boys whose mothers had labour started and hastened. They were 35 per cent more likely to have autism. Among girls, autism was not tied to induced labour, it was only more common in those born after labour was accelerated. They were 18 per cent more likely to have the developmental disorder than girls whose mothers had neither treatment. Autism affects about 1 in 88 U.S. children. Symptoms may involve communication problems including avoiding eye contact and unusual repetitive behaviour. Causes are uncertain but experts believe it probably results from a combination of genetics and other factors. These may include mothers' illnesses and medication use while pregnant, fathers' age at conception, and problems affecting the foetus during childbirth - all suggested but not proven in previous research. The study's biggest strength is bolstering the growing consensus that risks for autism occur before birth or soon after, said Dr. Byron King, director of Seattle Children's Hospital's autism centre. He was not involved in the study.