Prolonged exposure to anaesthetics has been shown to cause brain abnormalities in young animals, which was the impetus behind these two studies.

Not only did the researchers find that the use of anaesthesia during delivery was not harmful to the baby, they found that babies delivered by caesarean using an epidural anaesthetic (which numbs only the lower region of the body and does not involve the mother going to sleep) had a substantially reduced risk for learning disabilities later in life.

'The risk was reduced by about 40 percent compared to children delivered vaginally and those delivered via caesarean section but with general anaesthesia,' says Sprung, according to a Mayo Clinic release.

Study co-author and Mayo Clinic anaesthesiologist Randall Flick cautions that because

this study is preliminary, changes to medical practice should not be considered at this point. 'What we've found is an association between two things,' he says.

These findings are reported in the current issue of Anaesthesiology.