According to a new register study in the scientific journal BMJ, researchers at Karolinska Institutet are able to dismiss previous claims that there is a link between the increased use of antibiotics in society and a coinciding rise in childhood asthma. The study includes half a million children and shows that exposure to antibiotics during pregnancy or early in life does not appear to increase the risk of asthma.

 Several previous studies have shown that if the mother is given antibiotics during pregnancy or if a small child is given antibiotics in early life, the child has an increased risk of developing asthma. These studies have led to a widespread belief of a causal link. However, according to the researchers at Karolinska Institutet, there is reason to question the results of these studies.

 “Thanks to the Swedish population based registers we have been able to conduct a study designed to include factors that were previously not included. Our results show that there does not appear to be a causal link between early exposure to antibiotics and asthma, which is also valuable from an international perspective,” says Anne Örtqvist, physician and doctoral student at the Department of Medical Epidemiology and Biostatistics at Karolinska Institutet.