Generating expected growth curves and Z-scores for premature infants.

OBJECTIVE

To establish a standard for expected growth of premature infants and generate Z-scores based on the standard.

STUDY DESIGN

Multiple regression and analysis of variance were used to evaluate whether the 10th, 50th, and 90th percentiles of birth weight, head circumference, and length from other studies were statistically different from the percentiles from Riddle. Z-scores were generated from the 10th, 50th, and 90th percentiles.

RESULT

The growth charts from Mead-Johnson, Babson, Williams, Alexander, Usher, Yudkin, and Fenton were not coincident with the values reported by Riddle. The percentiles reported by Thomas were statistically coincident with the percentiles reported by Riddle.

CONCLUSION

The regression equations for the 10th, 50th, and 90th percentile for weight, head circumference, and length provide expected growth of premature infants. The equations can be used to generate expected growth curves and Z-scores for weight, head circumference, and length of premature infants.