Against the backdrop of a high prevalence of prematurity, limited research on the growth of very low birth weight (VLBW) preterm infants, and the availability of a reformulated fortifier c(RF), the study aimed to compare in-hospital growth of such infants receiving exclusively human milk fortified with either of two different formulations in a tertiary South African hospital. The intakes and growth of VLBW babies on the Original Fortifier were compared to those on RF in a prospective comparative efficacy approach. The daily consumption was determined using the reported composition of fortified preterm and mature milk. The primary result was the change in z scores from the beginning to the end of fortification for weight (WFAZ), length (LFAZ), and head circumference (HCFAZ) for age. Weight gain velocity, as well as gains in length and head circumference (HC), were also calculated.

Fifty-eight newborns were given OF for 16 days, while 59 were given RF for 15 days. RF had a considerably greater protein-to-energy ratio than OF. WFAZ and LFAZ declined in both groups, but HCFAZ improved marginally. There were no significant variations in z scores, weight gain velocity, length, or HC gain between the two groups. Despite a minor increase in protein intake and protein-to-energy ratio, VLBW babies on RF did not develop any faster than those on OF during their hospital stay.\