['A comparison of the effects of early (<2 h) and late (>or=2 h) discontinuation of prostaglandin E1 (PGE1), on systemic oxygenation following a successful balloon atrial septostomy (BAS), in neonates with confirmed diagnosis of d-transposition of the great arteries (d-TGA).', 'Neonates with a postnatal diagnosis of d-TGA who were admitted to a quaternary neonatal intensive care unit between January 1999 and December 2004 were identified from the local database. The effects of time of discontinuation of PGE1 on oxygen saturations, oxygen requirement, need for reinstitution of prostaglandin infusion and postoperative stability were analyzed.', 'Sixty neonates with a diagnosis of d-TGA were identified, 45 of whom had a BAS performed. Of these, 25 cases had early (<2 h) discontinuation of PGE1 whereas in the remaining 20 discontinuation was late (>or=2 h). PGE1 infusion was recommenced in 20 neonates (20/45 (44%)) after a successful BAS due to rebound hypoxemia. Of these, there was a threefold increase in the need for reinstitution of prostaglandin in the early compared to late discontinuation group (16/25 (64%) vs 4/20 (20%), P<0.006). There was no difference in postoperative cardiorespiratory stability.'] Is early discontinuation of intravenous prostaglandin E1 after balloon atrial septostomy associated with an increased risk of rebound hypoxemia?