Incidence and timing of germinal matrix/intraventricular hemorrhage in low birth weight infants.

Incidence and time of onset of germinal matrix/intraventricular hemorrhage (GM/IVH) were prospectively ascertained in 1,105 infants weighing < or = 2,000 g at birth, a cohort comprising about 85% of all births of that weight born from September 1984 to June 1987 in the central New Jersey counties of Ocean, Monmouth, and Middlesex. Cranial ultrasonography was performed as nearly as possible to age 4 hours, 24 hours, and 7 days. Each scan was reviewed by two independent readers and, if necessary, a third; consensus was achieved on scan of first diagnosis of GM/IVH in 965 of the 1,079 infants with assessable scans. The cumulative incidence of GM/IVH in the first week of life was 24.6% (265/1,079). In the 965 infants with consensus diagnoses, the first scan, at 4.9 +/- 2.2 hours, yielded the highest incidence--10.6% (95/899). Incidence by the second scan (25.1 +/- 4.9 hours) was 6.0% (49/813), and by the third scan (7.2 +/- 0.8 days), 9.0% (64/715). The iterative algorithm for interval-censored data developed by Turnbull (J R Stat Soc [B] 1976;8:290-5) was used to estimate the most likely time of onset based on time of first diagnosis. From 34% to 44% of hemorrhages were present at the first opportunity to scan, which in these data was at age 1 hour. At least a third of GM/IVH in infants < or = 2,000 g appears to be of congenital or immediate postnatal onset.