Patent ductus arteriosus in preterm infants

In preterm infants closure of the ductus is delayed, remaining open at 7 days of age in approximately 2% of infants born at 30-37 weeks’ gestation, 65% of those born at 25 through 28 weeks’ gestation, and 87% of those born at 24 weeks’ gestation.[14] The ductus is likely to close without treatment in infants born at >28 weeks’ gestation (73%),[15] in those with birth weight >1000 g (94%),[16] and in infants born at 26-29 weeks’ gestation who do not have respiratory distress syndrome (93%). [17] Data from placebo arms of controlled trials demonstrate that spontaneous ductal closure among smaller, less mature infants with respiratory distress syndrome is frequent. In the Trial of Indomethacin Prophylaxis in Preterms which included infants with birth weight from 500 to 999 g, 50% of placebo recipients never developed clinical signs of a PDA. [18] In a trial of early versus late indomethacin treatment of infants born at 26-31 weeks’ gestation in which PDA was confirmed by echocardiography on day 3, the ductus closed spontaneously by 9 days of age in 78% of those randomized to late intervention. [19] In a cohort of 842 infants, a haemodynamically significant PDA occurred in 70% (106/151) of infants born at 23-24 weeks and in 59% (405/691) of infants born at 25-28 weeks of gestation. [20]