Relationship between Duration of Infant Exposure to a Moderate-to-Large Patent Ductus Arteriosus Shunt and the Risk of Developing Bronchopulmonary Dysplasia or Death Before 36 Weeks

Infants < 28 weeks' gestation required at least 7 to 13 days of exposure to a moderate-to-large PDA before a significant increase in the incidence of BPD/death was apparent. Once this threshold was reached additional exposure to a moderate-to-large PDA did not significantly add to the increased incidence of BPD/death.