It is intended to examine the short-term and long-term efficacy and safety of intravenous immunoglobulin(IVIG) for the bronchopulmonary dysplasia in preterms born at 28 weeks and below. Participants will received continuous infusion IVIG 1 g/kg/day for the first 2 days, 0.5 g/kg/day for next 3 days (total does 3.5 g/kg), repeatable if necessary.
Gestational age ≤ 28 weeks + 6 days
Admission within 24 hours after birth.
Clinical presentation and chest X radiograph changes of BPD
Major congenital anomalies(e.g., congenital heart disease, congenital craniocerebral deformity, congenital structural abnormality of respiratory system, congenital hereditary metabolic disease)
Chromosomal defects (e.g., trisomy 13, 18, 21)
Severe intracranial hemorrhage
Multiple organ failure