Vitamin D, bone density, and nephrocalcinosis in preterm infants: a prospective study.

Background: Vitamin D (VitD) supplementation is recommended by the American Academy of Pediatrics (AAP) for preterm infants to improve bone density. Complications of VitD supplementation include hypercalciuria and nephrocalcinosis (NC). NC has been reported in 7-64% infants < 32 weeks gestational age (GA) or < 1500 g birth weight (BW).