Chen YCS, Mirzakhani H, Lu M, et al. - Since the role of prenatal vitamin D sufficiency and supplementation in the development of childhood aeroallergen sensitization and allergic rhinitis is unknown, researchers intended to determine if there is an association between prenatal vitamin D sufficiency and childhood allergic outcomes in candidates of the Vitamin D Antenatal Asthma Reduction Trial, a randomized controlled trial of prenatal vitamin D supplementation. This study included 414 mother-offspring pairs with offspring aeroallergen sensitization data available at 6 years of age. The authors discovered a protective effect of third-trimester prenatal vitamin D sufficiency on the development of clinical allergic rhinitis with aeroallergen sensitization at ages 3 and 6 years in mothers with first-trimester vitamin D insufficiency.