Patients deserve robust evidence on the health effects of donor milk and preterm formula

I thank Professor Coutsoudis and colleagues for their interest in my commentary “Repeating the errors of the past: the hazards of a commercial human milk industry”.¹ I am glad we concur on the need to prioritise provision of a mother’s own milk to her preterm baby, to guard against any perception that pasteurised human donor milk (pHDM) is equivalent, and on the many concerns around the rise of a for-profit commercial human milk industry. We are also in agreement about the obligation of all healthcare practitioners to advocate against non-evidence-based promotion of human milk products and to be honest in our discussions with parents. I suggest too that support for breastfeeding must extend beyond the hospital environment, to advocacy for legislation to ensure that women who breastfeed are protected from the financial and career progression penalties they currently face.

The evidence of benefit from pHDM  remains inconclusive, as I summarise in my commentary. This rests on meta-analyses that suggest lower NEC when preterm infants receive pHDM  in comparison with formula. However, these data are insecure, largely resting on small, methodologically weak studies that include medical NEC, a subjective diagnosis highly liable to ascertainment bias, and conflate sole and supplementary comparisons. Of note, neither sole nor supplementary comparisons show significant differences in mortality, invasive infection, or neurodevelopment, that would be important corroboration of benefit from pasteurised human milk. The Milk Trial (n = 483) cited by Coutsoudis and colleagues, compared pHDM and formula in extremely preterm infants receiving no or minimal milk from their own mothers.² This failed to complete recruitment but showed no significant differences in the primary outcome, 2-year neurodevelopment, or in mortality or bloodstream infection. There was lower medical NEC (secondary outcome) in the human milk arm, and details of surgical NEC were not provided.