OBJECTIVES: Pulmonary hypertension is associated with bronchopulmonary dysplasia in extremely low birth weight (ELBW) infants and contributes to morbidity and mortality. The objective was to determine the prevalence of pulmonary hypertension among ELBW infants by screening echocardiography and evaluate subsequent outcomes. METHODS: All ELBW infants admitted to a regional perinatal center were evaluated for pulmonary hypertension with echocardiography at 4 weeks of age and subsequently if clinical signs suggestive of right-sided heart failure or severe lung disease were evident. Management was at discretion of the clinician, and infants were evaluated until discharge from the hospital or pre-discharge death occurred. RESULTS: One hundred forty-five ELBW infants (birth weight: 755 6144 g; median gestational age: 26 weeks [interquartile range: 24-27]) were screened from December 2008 to February 2011. Overall, 26 (17.9%) were diagnosed with pulmonary hypertension at any time during hospitalization (birth weight: 665 6 140 g; median gestational age: 26 weeks [interquartile range: 24-27]): 9 (6.2%) by initial screening (early pulmonary hypertension) and 17 (11.7%) who were identified later (late pulmonary hypertension). Infants with pulmonary hypertension were more likely to receive oxygen treatment on day 28 compared with those without pulmonary hypertension (96% vs 75%, P , .05). Of the 26 infants, 3 died (all in the late group because of cor pulmonale) before being discharged from the hospital. CONCLUSIONS: Pulmonary hypertension is relatively common, affecting at least 1 in 6 ELBW infants, and persists to discharge in most survivors. Routine screening of ELBW infants with echocardiography at 4 weeks of age identifies only one-third of the infants diagnosed with pulmonary hypertension. Further research is required to determine optimal detection and intervention strategies. Copyright © 2012 by the American Academy of Pediatrics.