Multiple studies have found an association between prenatal and infant exposure to paracetamol and the development of asthma in childhood. But confounding factors, such as the indication for paracetamol use, have not always been taken into account.
In a study, published in the International Journal of Epidemiology (online, 9 February 2016)
, researchers studied data on 53,169 three-year-old children whose mothers were enrolled in a cohort study during pregnancy.
Prenatal exposure to paracetamol was independently associated with a 13% increased risk of asthma, after adjustment for indications including respiratory tract infection, pain and fever. Infant exposure to paracetamol was linked to a 29% increased risk of asthma.
Paracetamol is currently the recommended painkiller for pregnant women and the researchers, from the Norwegian Institute of Public Health, say their results do not warrant any changes to that guidance.
 Magnus MC, Karlstad O, Haberg SE, et al. Prenatal and infant paracetamol exposure and development of asthma: the Norwegian Mother and Child Cohort Study. International Journal of Epidemiology 2016; doi: 10.1093/ije/dyv366.