Management of bone health in preterm infants

APA: serum alkaline phosphatase activity; HMF: human milk fortifier; IU: international units; P: serum phosphorus; VLBW: very low birth weight (<1500 g).

* Risk factors for neonatal rickets include VLBW (<1500 g), birth weight 1500 to 1800 g with suboptimal mineral intake (eg, sole nutrition from unfortified human milk), long-term parenteral nutrition (>4 weeks), bronchopulmonary dysplasia treated with loop diuretics and fluid restriction, long-term corticosteroid use, or history of necrotizing enterocolitis.

¶ We suggest enteral vitamin D 5 mcg (200 units) daily for infants <1500 g and 10 mcg (400 units) daily for those ≥1500 g. Some authorities prefer to give 10 to 12.5 mcg (800 to 1000 units) daily; this dose is safe for infants >1500 g but is unlikely to affect disease course because neonatal bone disease is primarily caused by calcium and phosphorus deficiency. Infants with cholestasis or kidney disease may require higher doses of vitamin D and laboratory monitoring of vitamin D status. Either vitamin D2 (ergocalciferol) or vitamin D3 (cholecalciferol) may be used.

Δ Measure serum APA and P beginning 4 weeks after birth, then every 2 weeks until the infant is on full enteral feeds and APA values are decreasing.

◊ Targets for mineral intake are calcium 150 to 220 mg/kg/day and phosphorus 75 to 140 mg/kg/day. The high end of these ranges should be used for infants with radiographic evidence of rickets or for those who develop biochemical signs of bone disease (elevated APA or low P) while on lower levels of mineral supplementation.

§ Switching from high-mineral content sources should be delayed in infants who have additional risk factors for rickets (eg, prolonged parenteral nutrition or fluid restriction of <150 mL/kg/day).