We developed and evaluated a transducer holder and calibrated, spring-loaded applicator for the Ladd intracranial pressure monitor. The transducer holder/applicator combination allows reproducibility of application pressure and assures coplanarity of the transducer and the skin of the anterior fontanel. Measured transfontanel pressure (TFP) increased with increasing application pressure. Mean TFP was 9.1 +/- (SD) 2.6 cm H2O with an application pressure of about 10 g/cm2 in a group of healthy preterm and term infants at 6 h postnatal age. Birth weight, gestational age and mode of delivery did not affect TFP, allowing use of a single normative value and set of confidence limits in all infants at 6 h of postnatal age.