High-Risk Criteria for Rickets in Preterm Infants

Born at <27 weeks’ gestation
Birth weight <1000 g
Long-term parenteral nutrition (eg, >4 to 5 weeks)
Severe bronchopulmonary dysplasia with use of loop diuretics (eg, furosemide) and fluid restriction
Long-term steroid use
History of necrotizing enterocolitis
Failure to tolerate formulas or human milk fortifiers with high mineral content