Exposure to antibiotics in the womb or in early infancy is generally not associated with autoimmune-related diseases such as SLE or juvenile idiopathic arthritis, a cohort study suggests.

Researchers used data from the South Korean National Health Insurance Service to analyse 2.7 million children whose mothers were diagnosed with an infection during pregnancy.

One and a half million were exposed to antibiotics in utero, and 1.2 million were not.

The researchers also analysed 3.3 million children who had infections before six months of age, of whom 1.9 million received antibiotics, before tracking the development of six diseases: type 1 diabetes, juvenile idiopathic arthritis, ulcerative colitis, Crohn’s disease, SLE and Hashimoto’s thyroiditis.