The study will enroll premature, low birth weight infants in the Neonatal Intensive Care Units (NICU). Potential study subjects will be identified upon delivery, or transfer to the NICU, and notification by the neonatology service. Infants born at less than 30 weeks gestational age, birth weight less than or equal to 1500 grams will be eligible for enrollment in the study. The purpose of the study designed is to compare the splanchnic tissue oxygenation index and gut inflammatory biomarkers of patients with any stage of NEC with healthy controls. Since we will not be able to determine which patients will develop NEC a priori, we will anticipate enrolling up to 450 neonates to identify 15 neonates with NEC.