Although advances in early nutritional care of VLBW infants have reduced incidence of rickets of prematurity and osteopenia considerably, high risk infants may continue to have decreased bone mineral content which persists beyond 1 year of age (Abrams, 1989).
Risk factors for osteopenia include:
For very high risk infants it may be appropriate to routinely monitor bone status. Assessment may include:
Vitamin D: The AAP recommends that preterm infants receive 200-400 IU vitamin D in the hospital and after discharge. (Abrams, 2013)
Calcium and Phosphorus: Some studies suggest that infants fed nutrient enriched formulas with additional calcium and phosphorus show improvements in growth and mineral status (Lucas, 1992; Wheeler, 1996; Chan, 1994). For infants with osteopenia a modified transition from premature formula to standard formula or use of a commercial preterm post-discharge formula after discharge may be options. Use of premature formula after discharge should be carefully monitored to avoid excess intake of fat soluble vitamins (Vitamin A and Vitamin D). Infants at higher risk for rickets include those: born at <27 weeks gestation, with birth weight <1000 g, who received long-term parenteral nutrition, who had severe BPD with use of loop diuretics and fluid restriction, with long-term steroid use, with a history of nec, or who were unable to tolerate formulas or fortifiers with high mineral content (Abrams, 2013).
Hall found that at eight-weeks post discharge, a group of breastfed infants with birth weights less than 1800 g had lower incidence of hypophosphatemia and a trend toward lower alkaline phosphatase levels when breastmilk was supplemented. The regimen used in this study was 100 mg/kg/d of 10% calcium lactate and 50 mg/kg/d of phosphorus in the form of monobasic and dibasic salts. Both supplemented and non-supplemented groups received 400 IU vitamin D per day. This study suggests that some breastfed infants may benefit from increased calcium, phosphorus and vitamin D after discharge. Other investigators, however, have demonstrated spontaneous improvement in bone mineral content of breast fed babies after discharge (Congdon, Bishop). For infants with significant osteopenia, modified transition from fortified breastmilk or supplementation with premature formula may be options. Use of calcium and phosphorus supplements may not be tolerated and may result in abnormal calcium/phosphorus balance and requires close monitoring.