['Some preterm infants with a Grade 1 intraventricular hemorrhage (IVH) are subsequently found to have a Grade 3 or 4 IVH, while in others the Grade 1 resolves without extending.', 'We identified all neonates in our health system in the past 6 years with a Grade 1 IVH and compared those where the hemorrhage extended versus resolved.', 'Grade 1 IVH was identified in 417 neonates; 24 subsequently became a Grade 3, and 22 a Grade 4. These 46 were born earlier, 25 ± 2 weeks versus 30 ± 3 weeks (p = 0.000), with lower birth weight, 811 ± 284 g versus 1432 ± 603 g (p = 0.000); lower 5-minute Apgar scores, 5 ± 2 versus 8 ± 2 (p = 0.000); and slightly lower cord pH, 7.24 ± 0.16 versus 7.28 ± 0.10 (p = 0.009). Older gestational age was the most significant contributor lowering the odds of IVH extension (odds ratio [OR], 0.95; 95% confidence interval [CI], 0.92-0.98). Administering a red blood cell (RBC) transfusion up to and on the day the Grade 1 was detected was the most significant contributor increasing the odds (OR, 2.92; 95% CI, 2.19-3.90) of extension. In both groups (resolving vs. extending) criteria for ordering transfusions were similar as was the proportion of transfusions given out of compliance with guidelines.'] Is red blood cell transfusion of preterm neonates with a Grade 1 intraventricular hemorrhage associated with extension to a Grade 3 or 4 hemorrhage?