Inclusion Criteria:

• Premature newborn infant of either gender with a birth weight of 500 to 1000 grams, appropriate for gestational age;
• Non-symptomatic PDA with evidence of ductal shunting documented by an echocardiogram (ECHO);
• Less than 72 hours of age at the time of randomization;
• If infant is one of a multiple birth, he/she is one of the two (2) oldest infants who meet the eligibility criteria;
• Consent form signed by parent.

Exclusion Criteria:

• Either major congenital malformations and/or chromosomal anomalies;
• Proven, severe congenital bacterial infection;
• Maternal antenatal nonsteroidal anti-inflammatory drug (NSAID) exposure < 72 hours prior to delivery;
• Treatment with pharmacological replacement steroid therapy at anytime since birth;
• Unremitting shock requiring very high doses of vasopressors (i.e. inability to maintain mean arterial blood pressure appropriate for gestational age ± 2 SD using volume and maximal vasopressor therapy as defined by the individual institution);
• Renal failure or oliguria defined as urine flow rate < 0.5 mL/kg/hr in the 8 hours prior to randomization (Anuria is acceptable if infant is in first 24 hours of life);
• Platelet count < 75,000/mm 3;
• Clinical bleeding tendency (i.e. oozing from puncture sites);
• Expected survival less than 48 hours in the opinion of the attending neonatologist;
• Participation in other clinical intervention trials. Exceptions may be made if approved by Medical Director or designee, RPD Pharmaceutical Department;
• Symptomatic PDA as documented by 3 of the following 5 criteria
• Bounding pulse
• Hyperdynamic precordium
• Pulmonary edema
• Increased cardiac silhouette
• Systolic murmur Or, in view of the neonatologist is deemed to have a hemodynamically significant ductus.
• Exposure to NSAIDs at any time since birth.