Project Summary Early childhood caries (ECC) disproportionately affects children from low-income households and ethnic minority communities. Dysbiosis of oral microbiota, including enrichment of cariogenic bacteria and yeast, increase the risk for ECC. Previous research indicated connections between in-utero and early-life nutrition intake and gut microbiome development. Yet, the impact of in-utero and early-life nutrition intake on maternal and children’s oral microbiome remains unclear. As an augmentation to the parent award R01DE031025 Oral Microbiome in Early Infancy (OMEI), we propose this supplement OMEI + Nutrition. The parent OMEI studies the early-life biological factors underlying ECC racial disparity via a valuable underserved birth cohort. In the OMEI+ Nutrition supplement, we expand the factors to include perinatal nutritive (such as dietary iron intake) and nonnutritive behavior (such as pica) to examine their potential relationships with oral microbiomes during pregnancy and early life. Our central hypothesis is that mothers with nonnutritive eating behavior are associated with a distinct oral microbial community, which influences oral microbiome development in early childhood. We propose the following aims in the OMEI + Nutrition study. Aim 1: Assess the effect of nutritive and nonnutritive eating behavior on the oral microbiome of pregnant women. Aim 2: Assess the impact of maternal nutritive and nonnutritive eating behavior on infants' early-life (birth to 6 months) oral Candida colonization and yeast infection. Aim 3 (Exploratory): assess microbial compositions of pica substances. The OMEI + Nutrition will be the first study that examines the relationship between nutritive (such as dietary iron intake) and nonnutritive (such as pica) factors on perinatal oral microbiome among underserved US pregnant women and their children. Data generated will strengthen the understanding of children’s oral microbiome development and their association to ECC. Additional risk factors revealed from this OMEI+ Nutrition would be used as targets for prenatal counselling, ECC early prediction and prevention, specifically suitable for underserved women and children. This OMEI + Nutrition will be conducted by the diversity supplement applicant, Dr. Brenda Abu, a Nutritionist-Researcher, who will add her strong nutrition and dietetics background to the already integrated health disparities research team. Dr. Abu enthusiastically intends to develop her career in the interaction of nutrition and oral health among the underserved population. This OMEI + Nutrition supplement will advance her skills and expertise in oral health and oral microbiome research, which will build a solid foundation for a future R01 application that assesses eating behavior and oral microbiome on maternal and children’s oral and systemic health.