Bronchopulmonary Dysplasia (BPD) affects approximately one-fourth of very low birth weight infants (VLBW). The effects of increasing caloric density (above 24 kcal/oz) on growth, calcium metabolism and bone mineral status are unknown.

Primary Aim: To compare the effects of different feeding strategies on calcium absorption in VLBW infants with and without BPD.

Infants may be on any feeding strategy at the time of enrollment, however after enrollment they will be placed on one of the following 4 feeding regimens based on the presence or absence of BPD and the availability of at least 50% of feeding of human milk: 1.) Fortified Human Milk 24 kcal/oz, no BPD: Feeding volume 150cc/kg/day (n=15); 2.) Fortified Human Milk 27 kcal/oz, BPD: Feeding volume 133cc/kg/day (n=15); 3.) Premature Formula 24 kcal/oz, no BPD: Feeding volume 150cc/kg/day (n=15); or 4.) Premature Formula 27 kcal/oz, BPD: Feeding volume 133cc/kg/day (n=15).

Sample size (n = 60) was chosen such that a significant difference in intake-adjusted fractional calcium absorption of 10% could be identified (null hypothesis being accepted would be < 10% difference) based on a predicted mean 55 ± 8% calcium absorption. Differences are not expected between human milk and formula groups so data from these may be pooled for comparison of 24 vs 27 kcal/oz feedings in determining effects on both group and calcium absorption.

Inclusion criteria: 1.) Delivery at 23-30 weeks gestation by best estimate from maternal dates, prenatal U/S and newborn exam; 2.) Birth weight 500-1800 g; 3.) Transfer to TCH by 60 days of age; 4.) Achievement of full enteral feeds (>/=100 mL/kg/d) by 34 6/7 weeks post-menstrual age (PMA); 5.) Tolerance of >/= 100cc/kg day of enteral feeds for 5 days; 6.) Ability to tolerate feedings of preterm formula or fortified human milk (HM); 7.) Evidence of no BPD or mild-moderate BPD

We have studied 17 infants thus far in the protocol. One infant was dropped from the study due to issues not related to the study. We have no conclusions or interim data to report at this time.