The authors speculated that the improvement in the growth outcomes may have been due to changes in the infants’ nutritional management, such as the use of more aggressive parenteral nutrition and more caloric post-discharge formulae. Theile et al. [20] retrospectively studied 88 extremely low birth weight infants with BPD, and found a reduction in post-natal growth retardation at the time of hospital discharge (as assessed on the basis of weight and head circumference) in infants fed caloric-dense milk