All in the Name of Human Milk Tissue

Jae Kim, MD, PhD / December 2018


I remember closely following past efforts to create a substitute for the human red blood cell that could be as effective as donated blood. Unfortunately, despite various efforts by researchers and industry, we are still far from this, and depend on altruistic blood donation to support the need for more red cells in medicine. Messy as it seems, we will need to strongly support this industry until something truly substantial comes along.

Many of our preterm infants in the NICU get anemic and ultimately require one or more packed red blood cell transfusions to boost up their cell count to ensure optimal oxygen carrying capacity for their organ health. There is still a hot debate as to what level of anemia is the best level to transfuse at, but once that threshold is decided, practically all infants end up receiving a blood product. There are few circumstances I am aware of when an infant who consistently meets criteria for transfusion does not get one. Blood is not available in rare circumstances, typically from antibody compatibility issues.

Human milk is liquid tissue like blood

The scenario for human milk intake can be thought of in a similar manner, since human milk is a liquid tissue like blood, and gives life-saving benefits to all newborn infants, including preterm ones. Like blood, the handling of human milk tissue is a complex process. However, we are far more casual and less stringent with respect to human milk tissue. Certainly, tissue going into our circulatory system is different from what goes in our gut. But it seems we make far fewer demands for its quality, and demand it far less for our babies.

Why do we react so?

First, many of us still see human milk as a baby’s meal – food for sustenance – and not the complex liquid we now know it to be.

Second, we don’t classify it as a tissue in 50 States in the U.S., so it is handled like food and does not rise to the status of blood. I think what we call human milk has an impact on how we treat it. Perhaps we ought to be calling it human milk “tissue”. The evidence that human milk tissue has powerful effects on infant mortality and morbidity are greater than what nutrients alone can provide. The primary substitution of nutrient ingredients as we see with infant formula is no close parallel to mother’s milk.

Human milk tissue donors

Estimations of human milk tissue needs suggest that the available donor milk in the U.S. meets less than half of the gap needed in the care of preterm infants. Imagine if we were to understand that less than half of the needs for red blood cells were met by current donors. How would we react to this news? And what if the reason had less to do with the donors, but rather the blood banks that were procuring the blood? What if they did not have the facilities or equipment or personnel to recruit, test, collect, and distribute the blood? What would society say to that? How would you feel to know that if you were in a sudden motor vehicle accident, there only would be a 50% chance you could get life-saving blood? What if this were for your child undergoing emergency surgery?

The truth is, we are really short on human milk tissue for very low birth weight preterm infants. Too many infants receive less protective human milk tissue than they should. Too many suffer the consequences of severe and life-threatening bowel inflammation such as necrotizing enterocolitis. Many hospitals fall too short on maternal lactation support, and many still do not have access to or provide enough donor human milk tissue to fill the gap. One concern is that closing the gap may not happen before we start to see hospitals being penalized or sued for not providing human milk tissue (mother’s or donor) for all infants that need it.

Closing the gap

What should be our strategy to close the gap? First and foremost, is the optimum provision of mother’s milk, as this is significantly superior to donor human milk tissue, and so preference should be given to improving mother’s early lactation success and long term production.

The second step to closing the gap is using donor human milk tissue. Fortunately, there remains a large, replenishing pool of maternal donors out there who could meet a higher demand for volume of donor human milk tissue. The mistake I have seen several times, however, is gravitation towards adopting donor human milk as a priority over maternal milk production. This inverted approach should be avoided.

Human milk tissue

It may be time we started calling human milk what it is, a tissue, as I have done in this blog. Or, at least, recognize the status through policy and practice in the hospital. Bring up the comparison to blood with parents and colleagues when discussing how to make more maternal milk, and how to get access to adequate amounts of donor human milk tissue to fill the remaining gap. We need to move past this first epiphany of recognizing this wonderful biologic liquid to fully realize its potential.

We all need to do the hard work in building in the processes that maximize mother’s milk tissue production, and incorporates the use of donor human milk tissue no differently than what we do for life-saving blood tissue.

If you are struggling to find traction for these changes where you are at, perhaps you would benefit from a name change. Say “human milk tissue” three times… and go!


About the Author

Jae Kim is an academic neonatologist and pediatric gastroenterologist and nutritionist at UC San Diego Medical Center and Rady Children’s Hospital of San Diego. He has been practicing medicine for over 23 years both in Canada and the USA. He has published numerous journal articles, book chapters, and speaks nationally on a variety of neonatal topics. He is the Director for the Neonatal-Perinatal Medicine Fellowship Program at UC San Diego and the Nutrition Director of an innovative multidisciplinary program to advance premature infant nutrition called SPIN (Supporting Premature Infant Nutrition, He is the co-author of the book, Best Medicine: Human Milk in the NICU. Dr. Kim is a clinical consultant with Medela LLC.