The association of heparin exposure with intraventricular hemorrhage among very low birth weight infants.

To determine whether there is a relationship between exposure to heparin and an increased risk of intraventricular hemorrhage (IVH), we analyzed data from a cohort of infants who had been subjects in a randomized clinical trial of umbilical artery catheter placement. Data from 862 infants who survived the first 6 days of life were used for analysis. The incidence of IVH (grades 1 through 4) was 28.6%. The mean (SD) birth weight for infants with IVH was 954 gm (247 gm) compared with 1053 gm (253 gm) among infants without IVH (p < 0.01). The mean (SD) heparin intake among infants with an IVH was 83.5 units/kg/day (48.7) compared with 59.4 units/kg/day (48.7) among infants without an IVH (p < 0.01). With the use of logistic regression modeling to adjust for a number of potentially confounding variables, including fluid intake and birth weight, we observed an odds ratio for an IVH of 1.96 (95% confidence interval = 1.32, 2.91) for infants with second through fourth quartile intakes of heparin compared with that for infants with first quartile heparin intakes. Although we cannot rule out the possibility that the observations from this model may be confounded by factors associated with the severity of illness of the infant, these data support the findings of previous reports of an association between heparin exposure and the risk for an IVH.