A large-scale trial has found that the speed of increasing milk feed volumes in low birth weight or very low gestational age babies who are on intravenous feeding does not influence outcomes. This NIHR-funded study randomised preterm (below 32 weeks) or very low birth weight (less than 1,500g) babies to receive either daily milk feed increases in increments of 30ml per kilogram of bodyweight or 18ml per kilogram of bodyweight.
After two years of follow up, there was no significant difference in survival without moderate or severe neurodevelopmental disability between the groups. The two groups also had similar rates of serious infection, necrotising enterocolitis (a bowel disorder), and death.
This offers reassurance that faster introduction of milk through the nasogastric tube does not cause harm from bowel problems and that slower rates do not cause more infection from a longer need of the intravenous feeding line.
Why was this study needed?
In the UK, one to two per cent of babies are born at a very low birth weight (less than 1,500g) or are very premature (less than 32 weeks).
These babies are fed increasing volumes of milk each day through a small tube inserted into the nose or mouth and into the stomach until they reach full feeding volumes. They receive intravenous nutrition until they can digest nutritional volumes of milk.
Milk-feeding strategies may affect health long term as well as infant survival, but we don’t currently know how quickly to increase milk volume, and clinical advice varies. Limited previous evidence suggested faster rates may increase the risk of the severe bowel disorder, necrotising enterocolitis, while slower rates might increase the risk of sepsis due to longer periods of intravenous feeding.
What did this study do?
The Speed of Increasing Milk Feeds Trial (SIFT) compared faster (30ml per kilogram of body weight) with slower (18ml per kilogram of body weight) daily increments in milk feeding volumes.
This was a parallel-group randomised controlled trial conducted at 55 hospitals in the UK. Between 2013 and 2015, 2,804 infants born before 32 weeks gestation, with a birth weight of less than 1,500g, or both, were enrolled. At age two years, the primary outcome was assessed in 1,224 (87.4%) assigned to the faster increment feed and 1,246 (88.7%) assigned to the slower increment.
Caregivers were able to stop or alter the increase in feeding volume where clinically indicated. The trial was unblinded for practical reasons, but outcomes were reviewed by a committee who were unaware of trial-group assignments.
What did it find?
- At two years, survival without moderate or severe neurodevelopmental disability occurred in 802 of 1,224 infants (65%) assigned to the faster increment and 848 of 1,246 (68.1%) assigned to the slower increment (adjusted risk ratio [aRR] 0.96, 95% confidence interval [CI] 0.92 to 1.01).
- Late onset sepsis occurred in 414 of 1,389 infants (29.8%) in the faster-increment group and 434 of 1,397 (31.1%) in the slower-increment group (aRR 0.96, 95% CI 0.86 to 1.07).
- Necrotising enterocolitis occurred in 70 of 1,394 infants (5%) in the faster-increment group and 78 of 1,399 (5.6%) in the slower-increment group (aRR 0.88, 95% CI 0.68 to 1.16).
- At two years, death had occurred in 68 of 1,224 infants (5.6%) in the faster-increment group and 77 of 1,246 (6.2%) in the slower-increment group.
- Moderate or severe motor impairment occurred in 7.5% of the infants in the faster-increment group and 5.0% of those in the slower-increment group (aRR 1.48, 99% CI 1.02 to 2.14). There was no evidence of a significant between-group difference for other disabilities looked at.
What does current guidance say on this issue?
NICE does not provide specific guidelines on this, but NHS policy guidance for post-natal care of preterm babies states that enteral milk feeds should be increased by 30ml per kilogram of weight per day to a maximum of 150mls per kilogram per day on day four.
Decisions as to when to start, stop and alter the volume of milk feeding should be overseen by a paediatrician.
What are the implications?
These results provide evidence that either rate at which milk volume is increased can be used for this vulnerable group of babies.
The slightly increased motor impairment rate in the faster group was surprising and could possibly be down to chance, but this is a finding that could be incorporated into future trial design.
Citation and Funding
Dorling J, Abbott J, Berrington J et al. Controlled trial of two incremental milk-feeding rates in preterm infants. N Engl J Med. 2019;381:1434-43.
This project was funded by the NIHR Health Technology Assessment Programme (project number 11/01/25).
NICE. Postnatal care: breastfeeding and formula feeding. NICE Pathway. London. National Institute for Health and Care Excellence; 2019.
Senterre T. Practice of enteral nutrition in low birth weight and extremely low birth weight infants. World Rev Nutr Diet. 2014;110:201-14.
Produced by the University of Southampton and Bazian on behalf of NIHR through the NIHR Dissemination Centre