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Correspondence to: Dr Inder, Murdoch Childrens Research Institute and Howard Florey Institute, Royal Childrens Hospital, Flemington Rd, Parkville, Victoria 3052, Australia; [email protected]
Improvements in perinatal and neonatal care have contributed to a reduction in the overall incidence of intraventricular haemorrhage (IVH) in very low birthweight (VLBW, birth weight < 1500 g) premature infants from 40–50% in the later 1970s and 1980s to 20–25% in the 1990s.1,2 However, the 1990s have also seen increased survival of the extremely premature infant (birth weight < 750 g), who is at greatest risk of severe IVH and subsequent progressive posthaemorrhagic ventricular dilatation (PVD).3 The morbidity of PVD is appreciable. Up to 90% of infants have subsequent neuromotor disability, 76% exhibit pronounced disability, and 56% have multiple impairments.4 Studies of the natural history of PVD in the late 1980s suggested that about one third of infants with IVH develop PVD.5 Of VLBW infants with PVD, 85% subsequently had arrest of progression, spontaneous or induced by non-surgical intervention, and 15% required ventriculoperitoneal (VP) shunts for control of raised intracranial pressure.5 With an increased proportion of extremely preterm infants now surviving, the aim of this study was to define the incidence and natural history of PVD in VLBW infants in the 1990s and to define predictive factors for adverse outcome.
METHODS
Subjects
All VLBW infants with IVH admitted between September 1994 and September 1997 to the newborn intensive care units at Brigham and Women's Hospital and Children's Hospital in Boston and Christchurch Women's Hospital in New Zealand were identified. Diagnostic coding of IVH on neonatal discharge summaries was cross referenced with radiology records of all infants in each unit with a diagnosis of IVH on any cranial ultrasound report during the study interval. Cases identified were cross referenced against all infants with a birth weight of 1500 g or less admitted to each intensive care unit to ensure the validity of the cohort sample. Infants with chromosomal abnormality, congenital heart disease (patent ductus arteriosus excepted), and identified congenital abnormality of the central nervous system were excluded from the study. The mean (SD) gestational age of our cohort was 26.8 (2.6) weeks with a mean (SD) birth weight of 950 (306) g. The institutional research review boards...