(NEWSER) – A new study finds induced labor may be linked to an increased risk of autism, but doctors warn that more research is needed. The study of 625,000 children found that, overall, 13 out of every 1,000 boys and four out of every 1,000 girls developed autism. But, for boys, that rate was one-third higher when their mothers saw their labor induced or augmented, the BBC reports. (The effect was not as pronounced in female births.) LiveSciencereports that such augmentations might include strengthening contractions with hormone treatments; it says the risk of autism was 13% higher when labor was induced, 16% higher when it was augmented, and 35% higher (in male births) when it was both induced and augmented.