To determine whether oral or intravenous ibuprofen has a better or same efficacy and tolerance in closure of patent ductus arteriosis in extremely-low-birth-weight preterm infants.

To determine whether oral or intravenous ibuprofen has a better or same efficacy and tolerance in closure of patent ductus arteriosis in extremely-low-birth-weight preterm infants.Seventy ELBW preterm infants with patent ductus arteriosis will be enrolled in this prospective-randomized study. Patients will receive either intravenous or oral ibuprofen at an initial dose of 10 mg/kg, followed by 5 mg/kg at 24 and 48 h.

One of the following echocardiographic criteria of a duct size >1.5 mm, a left atrium-to-aorta ratio >1.5, left-to-right shunting of blood, end diastolic reversal of blood flow in the aorta, or poor cardiac function in addition signs of patent ductus arteriosis determined the need of ibuprofen treatment.

Inclusion Criteria:

• Birth weight below 1000 gram
• Diagnosed patent ductus arteriosis by Echocardiographic examination

Exclusion Criteria:

• Accompanied other congenital cardiac anomalies
• Severe thrombocytopenia < 60.000
• Severe intracranial bleeding (Grade 3-4)
• Intestinal abnormality and necrotising enterocolitis