The Effect of Maternal Milk on Tolerance and Growth in Premature Infants: A Hypothesis-generating Study

Early growth rates and feeding advancement rates of preterm infants are thought to influence later health. Feeding advancement is often difficult because of feeding intolerance. Exclusive human milk feeding improves tolerance, but can result in a lower weight gain rate. The addition of human milk fortifier has advantages for growth, but there are concerns that it may nullify the beneficial effect of human milk on tolerance. Therefore, the objective of the present study was to evaluate the relation between the amount of fortified human milk or formula and feeding tolerance and growth in preterm infants.

Patients (n = 174) participating in the TOL trial and born with a gestational age 30 weeks or younger were divided into tertiles according to the amount of human milk received during feeding advancement. Data on feeding tolerance during the advancement phase of enteral nutrition and anthropometrics were analysed.

The infants (n = 59) receiving the lowest percentage of their enteral intake as human milk (0%-57%) had the lowest amount of gastric residuals (P = 0.034) compared with the other 2 tertiles. Time to reach full enteral feeding and other tolerance parameters were not different among the groups. There was no dose response effect of the amount of human milk consumed on growth.

In preterm infants, an association between type of feeding (human milk vs infant formula) and time to achieve full enteral feeding or short-term growth was not found. Future prospective trials are needed to verify our results and focus on means to improve tolerance further.