When a baby is born prematurely or very prematurely, there are specific issues that need to be addressed regarding nutrition and protection from infections.
At first, premature babies can have difficulty tolerating any food that is introduced to its delicate system. The adaptation to normal feeding can pose problems for various reasons and until proper digestion is established, these babies receive nutrients via an intravenous line.1
Mother’s own milk
When a baby is able to digest breastmilk, the best food for a premature baby is raw, unpasteurized milk from his or her mother. In ‘Optimal feeding of low birth weight infants, the WHO writes: “There is strong and consistent evidence that feeding mother’s own milk to pre-term infants of any gestation is associated with a lower incidence of infections and necrotizing enterocolitis, and improved neurodevelopmental outcome as compared with formula feeding.” The benefits of breastmilk and its anti-infective components have been well established and is especially important for the protection of preterm infants. Please see ‘Why breastmilk?’ for more information on the antimicrobial properties of breastmilk.
Every effort needs to be made by the hospital staff to encourage and support the mother of a preterm baby to express her own milk. Separation, stress, fatigue and the possible precarious condition of the infant can affect milk production. Counseling mothers of preterm infants has been shown to increase the incidence of breastmilk feeding.2 In ‘Optimal feeding of low birth weight infants,’ the WHO concludes that when mothers are involved in the care and feeding of LBW infants, “substantial benefits in terms of improved breastfeeding rates and early discharge from hospital were reported when mothers participated in the care and feeding of their LBW infants in neonatal units.”
In ‘Sample Hospital Breastfeeding Policy for Newborns’ the American Academy of Pediatrics (AAP) writes that “Mothers who deliver prematurely may not be aware of the benefits of human milk for their preterm newborns and commonly base their decisions on health-related issues. Staff (physicians and nurses) will therefore stress the protective properties of breast milk and recommend mothers provide breast milk without necessarily making the commitment to breastfeed.”
The AAP further writes that “The first postdelivery encounter with the physician, or as soon as it is appropriate, should include discussion of human milk, its role in the preterm newborn’s care, and the urgency to begin expressing or pumping.” The AAP considers it to be the responsibility of the nursing staff to initiate and maintain an expressing or pumping routine. Per 3231 Breastfeeding: “The frequency and duration of milk expression directly correlates to the amount of milk produced. The mother should pump every 2 or 3 hours to mimic a baby’s natural feeding pattern. A tentative goal of 750-1000 ml per day by 10 days postpartum will help her maintain her milk supply throughout lactation.”
A recent study has investigated “the safety and feasibility of oropharyngeal (directly via the mouth between the gum and the cheek) administration of own mother’s colostrum drops to ELBW infants in a clinical setting.” Using mother’s colostrum in this manner requires a change in thinking, to view colostrum as a potential immune therapy and not simply as a feeding. As such, the oropharyngeal administration of colostrum can be an alternative to NPO (nothing by mouth/nil per os) status and/or a complement to trophic feeds in the first days of life for the ELBW infants.
The authors conclude: “Oropharyngeal administration of own mother’s colostrum is easy, inexpensive, and well-tolerated by even the smallest and sickest ELBW infants. Future research should continue to examine the optimal procedure for measuring the direct immune effects of this therapy, as well as the clinical outcomes such as infections, particularly ventilator-associated pneumonia.”
The amount of milk a premature baby needs is very small. However, when a mother of a premature baby is not able to express (enough of) her own milk, because of the optimal quality of breastmilk, donor milk should be obtained instead of taking recourse to breastmilk substitutes.
This perinatal and maternal-child health course for medical professionals states that studies have documented the following health benefits for preterm infants fed human milk:
- “Decreased incidence and/or severity of a wide range of infectious diseases
- Decreased post-neonatal infant mortality rates
- Decreased rates of SIDS in the first year of life
- Reduced incidence of both type 1 and type 2 diabetes, lymphoma, leukemia, Hodgkin’s disease, overweight and obesity, hypercholesterolemia, and asthma.”
Donor milk can be obtained via milk banks or from private donors (even though many hospital staff may refuse the latter). The donor guidelines from the Human Milk Bank Association of North America (HMBANA) and the National Institute for Health and Clinical Excellence (NICE) are very specific, mainly in order to protect sick and premature babies receiving this donor milk. Private donors can be screened to reduce exposure to pathogens, and the milk can be pasteurized if necessary. Please see ‘How can breastmilk be pasteurized at home?’ for more information on how to heat-treat. Please consult with specialized care provider if considering donating breastmilk to a premature baby.
There are always risks associated with feeding a baby anything other than his or her own mother’s breastmilk. When considering donor milk, parents are balancing the benefits of superior nutrition and immunity against the risk of disease transmission. Even after donor milk is screened, some argue that pathogens can still remain3 in the milk, and after donor milk has been pasteurized, pathogens can (re-)contaminate milk. Please see ‘Are there risks to using donor milk?’ for more information.
Risks of heat-treating
While milk banks are available for premature (or ill infants) in various countries, using banked milk is not always a possibility for parents because of lack of accessibility4 or lack of availability. Also, with proper screening, raw and fresh (not frozen) when possible is a better option for babies. In some countries, like Norway, milk banks have a long tradition of using raw breastmilk, even for premature babies. Screening and testing ensures the safety of this milk, rendering pasteurizing obsolete.
Most milk banks use the Holder method (62.5°C for 30 minutes) to pasteurize all breastmilk. It is the method used in the studies below. Studies show that pasteurizing breastmilk has potential health consequences for premature babies. Below are a few considerations that are especially important for premature infants, though they affect term infants as well.
Lactoferrin is an iron-binding protein with antimicrobial activity and is part of the natural defense of the body. Lactoferrin is found in milk and many mucosal secretions such as tears and saliva.
Lactoferrin is significantly affected by the Holder method of pasteurization. La Trobe table #7 compares the effects that different heat-treating and storage techniques have on breastmilk. As opposed to the Holder method which can destroy as much as 60% of the lactoferrin, flash pasteurization5 (72oC for 15 seconds) keeps the amount of lactoferrin intact which, as per Nutritional and physiologic significance of human milk proteins, is extremely important for (preterm) babies because it:
- assists in the digestion and utilization of nutrients from the milk, as well as
- contributes “to the defense of breastfed infants against pathogenic bacteria and viruses”;
- regulates immune functions, and
- is “likely to be involved in the development of the intestinal mucosa and other organs of newborns.”
In other words, lactoferrin assists in providing adequate nutrition to breastfed infants while simultaneously aiding in the defense against infection, and facilitating optimal development of important normal functions in newborns.
Regarding lactoferrin and flash-heating, this study writes: “The nutritional results were encouraging. The substantial decreases in the overall amount of lactoferrin observed with FH [flash-heating] and PP [Pretoria Pasteurization] may be attributable to partial denaturation of the lactoferrin, […] It is likely that such denaturation does not impair the biologic activity of lactoferrin.”
Flash-heating as well as flash pasteurizing would therefore be better options for the heat-treatment of breastmilk. Please see ‘Flash-heating’ for more information.
Lipase is an enzyme secreted in the digestive tract that causes the breakdown of fats into individual fatty acids that can be absorbed into the bloodstream.
This study evaluates whether pasteurizing milk (Holder method) reduces fat absorption and growth in Very Low Birth Weight (VLBW <1500 grams) infants. The authors conclude: “Feeding preterm infants pasteurized as compared to raw own mother’s milk reduced fat absorption. When the infants were fed raw milk, they gained more in knee–heel length compared to when they were fed pasteurized milk.”
Fats are not only important for energy and growth. They are also important for brain development. To develop the high-quality myelin needed for the nerves to transmit messages to other nerves throughout the brain and body, the body needs certain types of fatty acids –linoleic and linolenic– which are found in large amounts in human milk.6
The course for perinatal and maternal-child health states: “Lipase in human milk complements the low level of pancreatic lipase in infants, especially premature infants.” Lipase aids in the absorption of fats and is unfortunately mostly deactivated by all heat-treatment.
The authors of the above course also write that the milk of mothers of preterm babies is significantly different from that of mothers who deliver at term. Part of the reason that preterm milk is so important for premature babies and fat absorption is because “The lipids in human milk also provide nutritional benefits. The fat globules in preterm milk are smaller, aiding in their absorption directly from the immature gut. Premature infants lack the enzymes and bile salts needed for digestion of fats. However, they absorb more than 90% of the fats in human milk.”
Lack of lipase in pasteurized milk also has an impact on a premature baby’s immune response: the acetic acid produced by milk lipases act against lipid-enveloped viruses, bacteria and fungus.7 “Milk lipids provide an example of how an integral milk component can serve both a nutritional and a protective function.”8
Lipase is deactivated by heat-treatment, and therefore raw, fresh (not frozen) when possible, properly screened and handled breastmilk is a better option when available.
Immunoglobulins are a class of proteins produced in lymph tissue that function as antibodies in the immune response.
The study ‘Immunologic Factors in Human Milk: The Effects of Gestational Age and Pasteurization’ (Holder pasteurization) concludes “that although all factors analyzed had a significant reduction after pasteurization, total protein and IgA retained appreciable concentrations, especially in colostrum from mothers of both preterm groups, indicating that pasteurized preterm milk can be a beneficial alternative for feeding the preterm infant. Higher concentrations of proteins, IgA, and IgG in raw milk of the mothers of more preterm infants may be a compensatory protective mechanism for these babies, [bold –ed.] and a great effort should be made to feed the preterm with his or her own mother’s milk.”
This study on flash-heat treatment and immunoglobulins concludes: “Most breastmilk immunoglobulin activity survives FH, suggesting flash-heated breastmilk is immunologically superior to breastmilk substitutes. Clinical significance of this decreased immunoglobulin activity needs evaluation in prospective trials.”
Again, raw, fresh (not frozen) when possible, properly screened and handled breastmilk is a better option when available.
Flash pasteurizing has been demonstrated to inactivate most pathogens while maintaining high levels of lactoferrin, vitamins and immunoglobulins. Flash-heating has also been shown to deactivate HIV, and to be very beneficial in maintaining high levels of lactoferrin, vitamins and immunoglobulins.9 Flash pasteurizing would be a better way than the Holder method to render breastmilk safe for term and preterm babies alike. More research is needed in order to assess the effects of flash-heating on deactivating pathogens other than HIV. Please see ‘Flash-heating’ for more information. Eats on Feets is hoping to find sponsoring for future research on flash-heating with regards to the deactivation of those other pathogens. Raw, fresh (not frozen) when possible, properly screened and handled breastmilk is a better option when available.
In Donor Milk: What’s in It and What’s Not from the Journal of Human Lactation, the authors review some of the critical components of human milk and what is currently known about the effects of Holder pasteurization on their biological activity. Their conclusion is: “There are still more questions to be answered with regard to optimal nutrition for the preterm and very low birth weight infant. Preservation of the unique components of human milk during storage of mother’s own milk, storage and processing of donor milk, and the most effective fortification methods for human milk to meet the extraordinary needs of preterm infants are important areas for continued investigation. Our current state of knowledge indicates that human milk is optimal for full-term, as well as preterm infants, although any milk may require fortification to meet the special nutritional needs of the very low birth weight infant.”
In ‘Optimal feeding of low birth weight infants,’ the WHO writes that some studies suggest that donor milk from mothers of full-term infants cannot foster the same growth rate as mother’s own milk in preterm infants. Age-specific milk for preterm babies is therefore deemed important, and when possible, milk banks process this milk separately. Per ‘Avery’s Neonatology: Pathophysiology & Management of the Newborn,’10 “Most milk donated to milk banks comes from mothers who have delivered at term. However, they do receive milk from preterm mothers. Preterm and full term milk is processed separately. Donor and preterm milk can be specifically requested, and if available will be shipped to you.”
However, according to this study “some of these studies were done on donor ‘drip milk,’ or milk collected from the dripping of the opposite breast while the donor was breastfeeding her own full term infant. Drip milk has long been recognized to have lower fat content than expressed or pumped milk, since there is no active removal of the hind milk. There is also some question with regard to whether weight gain is the best measure of optimal outcome. One large study found that even with slower weight gain, the human milk fed preterm infants had significantly higher IQ scores at school age. Most donor milk banks today recognize the importance of using milk actively expressed or pumped to optimize fat content. Additionally, milk from mothers of preterm infants (gestational age 36 weeks or less) is designated as preterm milk for the first 4 weeks of pumping. It is processed in special batches, since it is higher in protein which is important for the preterm infant. Because mothers of preterm infants are being more actively encouraged to provide milk for their own babies, often they have excess to donate11 when their babies go completely to breast.”
For the purpose of making informed choices and in consideration of the above information, we encourage recipients (as well as donors) to research their options, to investigate milk bank procedures regarding heat-treatment, storage,12 distribution13 and usage,14 and to weigh the pros and cons of receiving milk from private donors or from a milk bank.
A note needs to be made about Bacillus cereus. B. cereus is a sporeforming bacterium that is found in nature (soil, crops, water) and causes food poisoning. Please see section ‘Bacteria’ for more information regarding Bacillus cereus.
The addition of human milk fortifiers (HMF) to breastmilk for Low Birth Weight (LBW) and Very Low Birth Weight (VLBW <1500 grams) babies also deserves a closer look. Please see ‘What about fortifiers and premature babies?’ for more information.
Please read this section about the suggested blood tests for donors and consult with a health care provider to see if privately donated milk is an option.
- In some cases, mothers and donors have improved the response of preterm babies to non-umbilical feeding by going on a restrictive diet and eliminating: gluten, dairy, nuts, chocolate, soy, corn and other known allergens. [↩]
- Sisk PM, Lovelady Ca, Dillard RG, Gruber KJ. Lactation counseling for mothers of very low birth weight infants: effect on maternal anxiety and infant intake of human milk. Pediatrics. 2006;117(1):e67-e75. [↩]
- Screening tests are designed to have a relatively high incidence of false positives in order to prevent any false negatives. While false positives happen to many people, pregnant or recently pregnant women tend to get them more frequently. From the perspective of a milk bank which will be testing the donors on a regular basis, it makes sense to exclude anyone with a history of false positives since the cost of pursuing confirmations at every testing opportunity is not only prohibitive for a non-profit org, it also can lead to logistical issues with the milk received from the donor. The study ‘Retrospective review of serological testing of potential human milk donors’ does not include follow up on the actual serological status of these women but, even per the most optimistic values, it is quite likely that many of these women did not in fact have any current infections. [↩]
- In the US, for instance, donor milk has a processing fee of around $4.50 per ounce of milk while insurance companies only cover donor milk when it is medically necessary. Donor milk is usually only available by prescription. In some countries, logistics may make it impossible to obtain breastmilk (distance, lack of dry ice, etc). [↩]
- Flash pasteurizing is not to be confused with flash-heating. While flash-heating has shown to deactivate HIV, the research has not addressed other pathogens, except theoretically. See ‘Flash-heating’ for more information. [↩]
- Per Ask Dr.Sears, Self-digesting fats. [↩]
- Per Riordan, Jan. Breastfeeding and Human Lactation. Third Edition 2005. p.105. Print. [↩]
- From ‘Human Milk Inactivates Pathogens Individually, Additively, and Synergistically’ [↩]
- See ‘How can breastmilk be pasteurized at home?’ for more information. [↩]
- Martha D. Mullett, and Mary M.K. Seshia. Avery’s Neonatology: Pathophysiology & Management of the Newborn. By Mhairi G. MacDonald. Sixth Edition ed. Lippincott Williams & Wilkins, 2005. 427. Print. [↩]
- When mothers of premature babies are counseled to increase their milk production in the first week or two after delivery they will be producing enough milk for a full term infant. This will be more than their infant can consume at that time, but will ensure that their milk production will meet the needs of their infant once the infant is discharged. [↩]
- BPNI writes: “Unless the milk being stored is for a mother’s own infant, banked milk is then pooled. […] It is thought to be beneficial because it averages out the immunological and nutrient content of the milk. The numbers are kept low so that any contamination can theoretically be traced back to its source. In Germany, however, pooling is not used because of the concern regarding contamination.” [↩]
- Not everyone who needs breastmilk will necessarily be able to obtain breastmilk from a milk bank. Please see this information from the FDA and this information from the Utah Breastfeeding Coalition about the priorities of milk banks in the US. [↩]
- Proper feeding options are important to reduce contamination of donor milk and infections in the infant. See ‘Are there risks to using donor milk?’ for more information. Also, donors should know that some milk banks serve for-profit companies. [↩]