ObjectiveTo compare the flow rates of formula various thicknesses through bottle nipples.DesignMultiple crossover design.SettingLaboratory experiment.ParticipantsNo human subjects.MethodsWe used established methods to test UltraPreemie; Preemie; Newborn; and Levels 1, 2, 3, 4 nipples with three formula: thin, slightly thick, mildly thick. We descriptive statistics calculate mean (milliliters pe...