More evidence is needed to determine whether donor breast milk is beneficial for babies in intensive care, argues a senior doctor in this week's BMJ.
Mother's milk is recommended for all babies, but mothers of preterm babies and other babies in intensive care are often unable to provide enough milk for their baby's needs. Donor breast milk and formula milk are options to make up the shortfall.
But the extent to which pasteurised donor breast milk retains the biological properties of mother's milk is uncertain and its place in present day neonatal intensive care is unclear, says Neena Modi, Professor of Neonatal Medicine at Imperial College London.
What evidence is there to support the use of donor breast milk, she asks?
A recent detailed analysis showed that donor breast milk reduced the risk of necrotising enterocolitis (a serious inflammatory condition of the bowel) when compared with formula, but infant growth was slower, and benefit was seen only when breast milk or formula was the sole source of nutrition. Current practice would be to use donor milk as a supplement to mother's milk and not as sole diet.
Only two studies have compared donor milk and formula as a supplement to mother's milk and neither found a significant difference in the rate of necrotising enterocolitis. For other outcomes, justification for using donor milk is largely anecdotal. Thus the role of donor breast milk in current neonatal practice remains to be established, she writes.
Furthermore, in contrast to blood banks that also provide a biological product, human milk banks in the UK conform to a voluntary code of practice but are otherwise unregulated.
So where does this leave us?
Human milk banks around the world have arisen through the voluntary efforts of committed individuals. Their altruism is undeniable, but unregulated expansion of human milk banking requires evidence of benefit, she says. Donor breast milk is also expensive. Although donors are unpaid, the cost of UK human milk banking (£30-150 per litre) is probably an underestimate of the full cost to the National Health Service.
Professor Modi believes that research is needed to determine whether donor milk, when used as a supplement to mother's milk, has short term or long term benefits (or both). At present there are less than 20 human milk banks in the UK but over 250 neonatal units and access to donor milk is very variable.
If donor breast milk is beneficial, clinical guidelines should reflect objective evidence, access should be equitable, and milk banking procedures should be consistent. If it is not beneficial NHS resources would be better directed towards supporting mothers' own lactation, she concludes.