Bronchopulmonary dysplasia (BPD) is diagnosed in approximately 40% of extremely preterm infants, those born before 28 weeks’ gestational age, and affects roughly 10,000 to 15,000 infants annually in the United States alone. Current treatment of BPD aims to not only aid in the survival of the infant but to also minimize further lung damage and promote physiologic growth to enhance lung development and repair. As the pathogenesis of the disease is multifactorial, including pre-, peri-, and postnatal factors, treatment and prevention approaches to BPD are diverse and include both medical treatment and ventilation strategies. Late postnatal steroids (> 7 days of life) have been proven to facilitate extubation and reduce the incidence of BPD in preterm infants. However, there is evidence that the use of steroids may contribute to increased rates of neurological impairment, including increased incidence of cerebral palsy. Given these findings, the American Academy of Pediatrics (AAP) guidelines recommend against the routine use of systemic steroids in the prevention of BPD and instead argues its use should be limited to infants who are considered extremely high-risk. The aim of this study is to determine whether the use of postnatal dexamethasone decreases the risk of developing BPD in a subset of high-risk infants, those with a concomitant diagnosis of necrotizing enterocolitis or late onset sepsis. A sample size of 200 extremely preterm infants with either necrotizing enterocolitis (NEC) and/or sepsis will be enrolled in a multi-center double-blinded randomized controlled trial comparing a low-dose dexamethasone taper and saline placebo. Infants will be evaluated for the development of BPD based on respiratory support and supplemental oxygen requirement at 36 weeks’ post-menstrual age (PMA). Infants will also be evaluated for presence of neurodevelopmental outcomes at 18- to 22-months follow-up. The results of this proposed study will build the evidence base for the safety and efficacy of postnatal steroids in the prevention of BPD in a subset of high risk, extremely preterm infants. This will help to establish a more detailed characterization of infants for which the benefits of steroids outweigh the risks. The results will enable clinicians to make more informed decisions regarding the medical care of extremely preterm infants and more accurately counsel parents on the incidence of subsequent BPD development, as well as long-term morbidities.