 In addition to the interventional trial above, the NRN is conducting a 6-month time-limited prospective observational study of all infants born at an NRN center between 23 and 26 weeks gestational age. All clinical decisions made for these babies will be at the discretion of the attending neonatologistinfant care team according to standard practice at each institution. Data on blood pressure management in the first 24 postnatal hours collected for each infant. 