CLINICAL REPORT Calcium and Vitamin D Requirements of Enterally Fed Preterm Infants

Bone health is a critical concern in managing preterm infants. Key nutrients of importance are calcium, vitamin D, and phosphorus. Although human milk is critical for the health of preterm infants, it is low in these nutrients relative to the needs of the infants during growth. Strategies should be in place to fortify human milk for preterm infants with birth weight <1800 to 2000 g and to ensure adequate mineral intake during hospitalization and after hospital discharge. Biochemical monitoring of very low birth weight infants should be performed during their hospitalization. Vitamin D should be provided at 200 to 400 IU/day both during hospitalization and after discharge from the hospital. Infants with radiologic evidence of rickets should have efforts made to maximize calcium and phosphorus intake by using available commercial products and, if needed, direct supplementation with these minerals. Pediatrics 2013;131:e1676–e1683 In 2011, the Institute of Medicine (IOM) released dietary guidelines for calcium and vitamin D intakes for all age groups.1 However, no intake recommendations were made specifically for preterm infants, because they were considered a special population and did not fit within the guidelines for dietary reference intakes developed by the IOM. Preterm infants have unique bone mineral requirements that may not be assumed to be similar to those of full-term newborn infants. Previous statements in the United States have limited their recommendations to full-term infants.2,3 However, The European Society for Pediatric Gastroenterology, Hepatology, and Nutrition has recently described enteral nutrition recommendations for preterm infants.4,5 Data on in utero bone mineralization rates are limited. Cadaver studies, beginning with the classic work of Widdowson et al,6 generally support an in utero accretion of calcium during the third trimester of 100 to 130 mg/kg per day, peaking between 32 and 36 weeks’ gestation. Phosphorus accretion is approximately half the accretion of calcium throughout gestation. Remarkably, more recent reevaluation of these data by using modern body composition techniques7 provided values similar to those developed by Widdowson et al.6 In full-term infants, there is a strong correlation between maternal and infant cord blood 25-hydroxyvitamin D (25-OH-D) concentrations, although the cord blood concentration is less than the maternal concentration.8 A substantial proportion of pregnant women, especially Steven A. Abrams, MD and the COMMITTEE ON NUTRITION