Bone ultrasound velocity in small- versus appropriate-for-gestational age preterm infants.

OBJECTIVE

To compare bone status of small-for-gestational age (SGA) versus appropriate-for-gestational age (AGA) newborn preterm infants.

STUDY DESIGN

Tibial speed of sound (SOS) was measured in 144 infants categorized as SGA or AGA using the reference tables of Lubchenco et al. and Alexander et al.

RESULTS

By the Lubchenco tables, 22% of infants were SGA and 75% were AGA. The mean gestational ages of SGA and AGA were similar (33.3+/-2.6 and 32.5+/-2.4 weeks, respectively, P = 0.09); however, SGA infant birth weights were lower (1329+/-392 and 1829+/-481 g, respectively, P<0.001). SOS values were higher for SGA versus AGA infants (3098+/-135 and 3003+/-122 m/s, respectively. P<0.001). Use of the Alexander tables yielded a twofold increase in the percent of infants categorized as SGA; SOS values remained significantly greater for SGA infants (P<0.001).

CONCLUSION

Higher tibial SOS values in SGA versus AGA infants indicate greater bone strength.