Antenatal corticosteroid administration and neonatal outcome in very low birth weight infants: The NICHD neonatal research network

Air leak: Extrapleural air diagnosed by CXR or thoracentesis; NICHD included pneumothorax or pneumopericardium; VT-OX included only pneumothorax. BW and ROSS included pneumothorax, pneumomediastinum, and pneumopericardium; BW also included pulmonary interstitial emphysema and pneumoperitoneum. Covariates GA: NICHD defined by best obstetric estimate; VT OX defined by best neonatology estimate. BW trials defined GA by menstrual history; if this GA differed by more than 2 weeks from the neonatologists’ estimate, the neonatologists estimate was used. RUM: NICHD used premature rupture of membranes (ROM) (ROM 2 1 hour before labor). ROSS analyzed ROM 2 24 hours; BW defined as 2 1 hour between ROM and delivery. Steroid treatment NICHD: Any form of corticosteroids given within 1 week of delivery; a complete course defined as 2 two doses for lung maturity with delivery occurring at least 12 hours after the second dose or at least 24 hours after the first dose. VT-OX: Any corticosteroid administered before delivery. A complete course defined as delivery occurring more than 24 hours and less than 1 week after any dose of corticosteroids. A partial dose defined as delivery occurring ~24 hours after the first dose or more than 1 week after the last dose of steroids. ROSS: Any corticosteroid administered before delivery. A complete course defined as ~two doses at least 12 hours apart with delivery occ&ing 24 hours to 7 days after first dose. Incomplete defined as any other steroid exposure. B W/BW TIND: Partial defined as < 24 hours from corticosteroid dose to delivery. Full defined as corticosteroid dose ~-24 hours before delivery.