Several studies have found associations between microbial infections during pregnancy and preterm delivery (PTD). We investigated the influence of food with antimicrobial and prebiotic components on the risk of spontaneous PTD. A literature search identified microbes associated with spontaneous PTD. Subsequently, 2 main food types (alliums and dried fruits) were identified to contain antimicrobial components that affect the microbes associated with spontaneous PTD; they also contained dietary fibers recognized as prebiotics. We investigated intake in 18,888 women in the Norwegian Mother and Child Cohort (MoBa), of whom 950 (5%) underwent spontaneous PTD (