Incidence of periventricular/intraventricular hemorrhage in very low birth weight infants: a 15-year cohort study.

OBJECTIVE To assess the incidence of periventricular/intraventricular hemorrhage (PIVH) in very low birth rate neonates. METHODS This was a prospective cohort study conducted on a sample of very low birth weight infants over a 15-year period. Neonates who did not undergo cerebral ultrasonography, had malformations affecting the central nervous system, or died within the first 24 hours of life were excluded. Ultrasonography was performed through the anterior fontanelle using an Aloka® 620 scanner with a 5 mHz probe, between days 1 and 3 of life, at 7 days, and at 28 days (or at discharge). Incidence was analyzed by means of the chi-square test for trend or Cochran-Armitage test and through a simple linear regression model with a logarithmic trendline as the output. For assessment of potential associated factors, a variety of obstetric, perinatal, and neonatal data collected between 1991-1994 and 2002-2005 were analyzed, using the chi-square and Fisher's exact tests for statistical analysis. The significance level was set at 5%. RESULTS Of 1,777 very low birth weight infants born during the study period, 1,381 (77.7%) were examined. Of these, 289 (20.9%) had PIVH. The yearly distribution of cases showed a progressive decline in incidence, from 50.9% in 1991 to 11.9% in 2005 (p < 0.0001). The incidence of PIVH decreased across all weight ranges as well as at grades I/II and III/IV. Significant differences in antenatal corticosteroid use, gender (male), weight (< 1,000 g), hyaline membrane disease, mechanical ventilation, administration of surfactant, patent ductus arteriosus, and sepsis were found. CONCLUSION The incidence of PIVH in very low birth weight infants declined significantly during the study period.