In the largest study to date to examine the association of maternal 25(OH)D concentrations in pregnancy with offspring asthma, atopy and lung function, we found no evidence of a relationship between maternal 25(OH)D concentration and childhood wheeze, asthma, atopy, eczema, hayfever, IgE or pulmonary function, and no suggestion that either high or low concentrations of maternal 25(OH)D were associated with an increased risk of these outcomes. This evidence concerns the gene IGHE and asthma.