Pyrhönen K, et al. - This study entailed an assessment of the incidence of pet (dog and cat) sensitisation according to the season of the 11th fetal week. Researchers also investigated if the link between pet exposure and respective sensitisation was modified by the coincidence of the 11^th fetal week with pollen season. Findings demonstrated that coincidence of the first fetal trimester with pollen season reinforced the link between pet exposure and respective sensitisation. Data also indicated that by deviating immune system towards Th2 type reactivity, early pregnancy pollen exposure may promote development of specific allergy in case allergen exposure occurred. Overall, it was concluded that primary prevention of allergic diseases may need to begin during early pregnancy.