Background  

Factors that affect quantitative ultrasound (QUS) bone measurements have not been clearly defined for all clinical populations.

Objective  

To determine some technical and clinical aspects that may affect QUS bone measurement in the neonate–maternal dyad.

Materials and methods  

Speed of sound (SOS) was measured at the radius and tibia using a commercial multisite axial transmission QUS instrument and three manufacturer-provided probes (CS, CR and CM).

Results  

The study included 183 singleton neonates and 159 mothers. The type of probe, weight and edema significantly affected SOS measurements. In infants, the CS and CR probes measured SOS consistently at the tibia but not the radius. Gestational age was predictive of SOS from the CS probe and remained significant when race, gender, and birth weight were included. None of these parameters predicted SOS when using the CR probe. Maternal SOS at the radius and tibia was correlated with the CM probe. Maternal SOS was predicted by age but not by gravid status, number of living children, or race. There was no consistent correlation between maternal–infant dyad SOS measurements.

Conclusions  

Axial transmission SOS of bone varies with probe and site and is affected by technical and clinical factors. Valid data depend on documentation of the probes used and the clinical population studied.