The Antenatal Risk Factors for Intraventricular Hemorrhage Study, also funded by NINCDS, was composed of 520 infants, at or less than 1,500 grams birth weight who were born at two Harvard teaching hospitals between July 1984 and September 1986. Babies were enrolled if they were alive when their mothers were interviewed, usually 24-48 hours after delivery. Procedures in the delivery room and findings on early examinations were recorded. Information about the first five days of life was collected daily.