Babies born in the context of extreme prematurity have the persistence of a vessel essential during the fetal life (the ductus arteriosus), which causes post-natally a redirection of blood flow to the lungs, flooding them with excessive blood, at the disadvantage of other organs, which become deprived of adequate blood supply. Many complications of prematurity have been attributed to the ductus arteriosus (cerebral hemorrhage, respiratory failure, intestinal necrosis) in observational studies. Several strategies to encourage closure of this vessel have been studied (closure with medication or surgical ligation), but have not been associated with an improvement in the adverse effects attributed to this vessel. These therapies, which may have significant side effects (renal injury, decreased cerebral blood flow, water retention), are still administered in most neonatal units in the very immature and fragile babies, despite the recommendations of the American Academy of Pediatrics to avoid their use.
Also, surgical ligation has been associated with many significant complications (vocal cord paralysis, post-surgical cardiac or pulmonary dysfunction). However, a conservative approach has not been proven to be safe in these immature and fragile babies, which, according to observational studies, seem to feel the impact of the persistence of this ductus arteriosus. No studies have been done to compare medical and surgical therapy leading to the closure of the ductus to a conservative approach of observation. The proposed study will compare a cohort of extreme premature newborns who did not have an intervention to a contemporary cohort who received treatments for the ductus arteriosus in order to promote closure. Thus, this study could provide some information on a practice that remains current in the majority of neonatal units taking care of babies born before 29 weeks of gestational age.