Abstract:OBJECTIE: To investigate the correlation of gestational age (GA) with carboxyterminal propeptide of type I procollagen (PICP), deoxypyridinoline (DPD), and bone sound of speed (SOS) in appropriate-for-gestational-age (AGA) neonates, as well as the relationship between bone turnover markers and bone SOS. METHODS: Sixty-five AGA neonates were included in the study. The neonates were divided into three groups: preterm infant (GA ≤34 weeks, 14 cases), late preterm infant (34 weeks