| Recruiting | 4 | 802 | Canada, US | Ampicillin, Gentamycin, Normal saline | Michael Morowitz, Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD) | Microbial Colonization, Extreme Prematurity, Early-Onset Neonatal Sepsis, Late-Onset Neonatal Sepsis, Necrotizing Enterocolitis of Newborn, Death; Neonatal | 09/26 | 06/27 | | |