['To determine whether the diastolic closing margin (DCM), defined as diastolic blood pressure minus critical closing pressure, is associated with the development of early severe intraventricular hemorrhage (IVH).', 'A reanalysis of prospectively collected data was conducted. Premature infants (gestational age 23-31\xa0weeks) receiving mechanical ventilation (n\xa0=\xa0185) had ∼1-hour continuous recordings of umbilical arterial blood pressure, middle cerebral artery cerebral blood flow velocity, and PaCO2 during the first week of life. Models using multivariate generalized linear regression and purposeful selection were used to determine associations with severe IVH.', 'Severe IVH (grades 3-4) was observed in 14.6% of the infants. Irrespective of the model used, Apgar score at 5\xa0minutes and DCM were significantly associated with severe IVH. A clinically relevant 5-mm Hg increase in DCM was associated with a 1.83- to 1.89-fold increased odds of developing severe IVH.'] Does elevated Diastolic Closing Margin be Associated with Intraventricular Hemorrhage in Premature Infants?