To help answer that question, Mukerji et al. (doi.:10.1542/peds.2015-0944) performed a systematic review and meta-analysis of studies on neurodevelopmental outcomes based on the severity of the PIVH. 21 studies were included in the meta-analysis—all observational. Although a good number of these studies suffered from one type of confounding bias or another, the aggregate analysis identified that even mild PIVH carried higher odds of having moderate to severe neurodevelopmental impairment.
Just why this phenomenon might be occurring in mild PIVH forms the basis of a most interesting commentary by pediatric perinatal neurologist Dr. Joseph Volpe (doi:10.1542/peds.2015-3553) who shares his thoughts as to why outcomes might be affected negatively even after a mild germinal matrix intraventricular hemorrhage. This review article and commentary are well worth reading and in turn sharing as needed with families of children who experienced all levels of PIVH severity to better enable them and you to monitor for neurodevelopmental delays and in turn implement early intervention services that might improve outcomes in this high risk infants.