Calibrated-orifice nipples for measurement of infant nutritive sucking.

To measure infant nutritive sucking reproducibly, nipple flow resistance must be controlled. Previous investigators have accomplished this with flow-limiting venturis, which has two limitations: flow resistance is highly dependent on fluid viscosity and older infants often reject the venturi nipple. This report describes the validation of calibrated-orifice nipples for the measurement of infant nutritive sucking. The flow characteristics of two infant formulas and water through these nipples were not different; those through venturi nipples were (analysis of variance; p < 0.0001). Flow characteristics did not differ among calibrated-orifice nipples constructed from three commercial nipple styles, indicating that the calibrated-orifice design is applicable to different types of baby bottle nipples. Among 3-month-old infants using calibrated-orifice nipples, acceptability was high, and sucking accounted for 85% of the variance in fluid intake during a feeding. We conclude that calibrated-orifice nipples are a valid and acceptable tool for the measurement of infant nutritive sucking.