Being born prematurely has been linked to an increased risk of autism but this could be due to complications in pregnancy and in and around birth rather than prematurity itself. A study of 7,296 children by researchers at the Karolinska Institute in Stockholm found that children who were born at 31 weeks or earlier were 1.5x more likely to develop autism while those born between 32-36 weeks were 1.3x more likely to develop it. However, after birth complications had been taken into account there were no significant differences between babies born at 36 weeks or earlier and those born later suggesting that it was the complications not prematurity itself that raised the risk of autism. Pre-eclampsia, being born small for the length of a pregnancy, low infant blood sugar, birth defects and infant seizures all raised the risk of autism; pre-eclampsia was found to raise the risk by 50%.
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