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The Apparent Breastfeeding Paradox: What is optimal nutrition for a premature baby?

Last week, I wrote about some of the unique challenges (and one potential solution) to breastfeeding a baby born prematurely. Another study recently published in BMJ Open provides more food for thought on breastfeeding preemies (1; full text available here).

A team of French researchers examined the relationship between breastfeeding, growth, and neurodevelopment in two observational cohorts of babies born very prematurely, at less than 32 or 33 weeks of gestation.

Between the two cohorts, a total of 2925 very preterm infants were included in the study. These babies were in the hospital for 50-60 days before they were allowed to go home. In the two cohorts, 19% and 16% of babies were breastfeeding at the time of discharge from the hospital. The study looked at associations between type of feeding at discharge (breast milk or formula), growth during hospitalization, and growth and neurodevelopment at 2 and 5 years of age.

Source: Wikimedia Commons

What were the findings? In these cohorts, formula-fed babies had gained more weight by the time they were discharged from the hospital. However, at 2 and 5 years of age, the formula-fed babies scored lower on neurodevelopment assessments compared to the breastfed babies. Breastfed babies also had greater head circumferences by 2 and 5 years of age, suggesting improved brain development, and they appeared to catch up to formula-fed babies in height and weight.

The study authors call this an “apparent breastfeeding paradox.” Preemies that are breastfed early in life may be slower to gain weight, but they have better neurodevelopment in the long-term.

Feeding babies born so prematurely is tricky. Human milk evolved to meet the nutritional needs of full-term infants. Until very recently in human history, a baby born at less than 32 weeks gestation wouldn’t have survived at all. Because they need to catch up in growth and development, premature babies need more protein and minerals than human milk can provide. Previous studies not accounting for effects of breastfeeding have found that preemies with inadequate growth during hospitalization are at risk for later cognitive dysfunction. In the NICU, these preemies are fed either a special enriched formula or human milk fortified with additional nutrients. They are initially fed through a gastric tube, so it is easy to add fortifier to human milk.

The tricky part comes when premature babies start to suckle and breastfeed. This is the ultimate goal, of course, but once a baby starts to suckle on her own, supplementing with formula is a disruption to the routine of breastfeeding. It can derail the process of building milk supply and a healthy, on-demand breastfeeding relationship between mom and baby. However, there is a fear that feeding breast milk only – without the additional nutrients – may compromise baby’s growth.

As a consequence, even when a mom has established adequate milk supply and her baby is breastfeeding well, it is controversial whether she should be encouraged to supplement with enriched formula. A 2007 Cochrane review (2) attempted to address the question of whether enriched formula or human breast milk is better for preemie babies. However, the authors found NO studies of high enough quality to answer this question. This is the shortest Cochrane review I’ve ever seen – the results section is just 4 sentences! Without any convincing evidence that feeding enriched formula provides advantages to preemies, the authors conclude that moms who wish to exclusively breastfeed should be encouraged to do so.

This most recent study should give some reassurance to parents and pediatricians about the value of breastfeeding premature babies. Most importantly, it tells us that weight gain in preemies isn’t everything. Sure, it is our easiest measure of a baby’s growth and development, but feeding a preemie with breast milk may provide benefits to brain development that are not immediately apparent. At the same time, we need to be careful about over interpreting this study, because growth is clearly important as well. We need more research on what constitutes inadequate vs. adequate growth in preemies fed breast milk vs. formula.

There were some limitations to this study. Like most studies of breastfeeding, it was observational in design. That is, the babies were not randomly assigned to breastfed and formula-fed groups – that would be unethical. Many of the factors that might influence the likelihood of a mother breastfeeding might also be related to the child’s neurodevelopment. The authors attempted to statistically account for several of these confounding factors, including mothers’ age, marital status, education, profession, and income. However, we can never “fix” all of the limitations of an observational study with statistics. For example, as the authors state, “the very ability of an infant to suckle may be associated with a less sick infant.” A further limitation was that breastfeeding was only recorded at the time of discharge. For one of the cohorts, breastfeeding status was known at 2 months, but beyond that, we don’t know how long these infants were breastfed. On the other hand, a significant strength of this study was that it found the same “breastfeeding paradox” in two independent cohorts of premature babies.

The authors of the study have the following recommendation:

“In conclusion, the neurodevelopment of premature infants is likely to benefit from feeding supplemented mother’s milk during hospital stay and unsupplemented mother’s milk after discharge…”

Despite the limitations and need for further research, these findings should reassure pediatricians and encourage mothers of preemies to breastfeed when possible, while keeping a close eye on baby’s growth and development.

REFERENCES:

1. Roze, J. C., D. Darmaun, C. Y. Boquien, C. Flamant, J. C. Picaud, C. Savagner, O. Claris, A. Lapillonne, D. Mitanchez, B. Branger, U. Simeoni, M. Kaminski and P. Y. Ancel (2012). “The apparent breastfeeding paradox in very preterm infants: relationship between breast feeding, early weight gain and neurodevelopment based on results from two cohorts, EPIPAGE and LIFT.” BMJ Open 2(2): e000834.

2. Henderson, G., T. Fahey and W. McGuire (2007). “Nutrient-enriched formula milk versus human breast milk for preterm infants following hospital discharge.” Cochrane Database Syst Rev(4): CD004862.

23 Comments
  1. Fascinating. I am the grandmother of a preemie-to-be due to my daughter’s Müllerian duct abnormalities/bicornuate uterus. As a mom I delivered 3 large (9 lbs + ) post-term babies so this is new territory for me.
    I find your blog very interesting and thank you for all the things I’ve learned here.

    Like

    April 20, 2012
    • And I’ve re-blogged this post. Thank you again.

      Like

      April 20, 2012
    • I find feeding preemies to be fascinating, too, and I’m inspired by the doctors, nurses, and parents that nurture babies in the NICU. I’m glad this is helpful to you. Good luck to your daughter, and enjoy your grandchild!

      Like

      April 20, 2012
  2. Reblogged this on To Talk of Many Things and commented:
    Absolutely Fascinating. As the mom of 3 very large post term babies my future as the grandmother of a preemie-to-be has me reading all things preemie. Always a proponent for breast-feeding this blog post was fascinating to me.

    Like

    April 20, 2012
  3. Excellent post! I think so many mothers get into the “how much does your baby weigh?” contest with each other, but that’s not really what’s most important in a child’s development. Breastfeeding supplies so many other benefits besides just caloric intake, that simply comparing weight gain in preemies would be useless. I love that this study took into account neural development after five years. Amazing how breastfeeding really does start your child off right. 🙂

    Like

    April 20, 2012
    • I think it is truly a delicate balance. Obviously if a preemie really isn’t growing well on breast milk alone, that’s telling us something. But if switching to exclusive breastfeeding means growth slows for a few weeks, that may be a small trade-off for the benefits of having a good breastfeeding relationship in the long run. I think we’re really just beginning to understand everything that is in breast milk – totally agree that it goes beyond calories and nutrients!

      Like

      April 20, 2012
  4. alison edwards #

    I have had a 31 weeker and a 33 weeker and have found that my breast milk had adapted to cater for the fact that my babies were born early. It was light and fluffy – and although I had to tube it to them initially before they coukd suckle, I also saw the heavy formula milk fed to the other babies on the ward being repeatedly thrown up by them as it was too heavy and gloopy for them to cope with. They then needed extra sisipride to keep it all down. More medicine…. pffff

    Like

    April 22, 2012
    • Very interesting observations! I’d like to learn more about how preterm milk differs from term milk. It is so fascinating.

      Like

      April 23, 2012
  5. This is a great post! I will definitely keep this in mind when I have little ones. Thanks for your thoughts.

    Like

    April 22, 2012
  6. Emily #

    Just breastfeeding my 27 weeker while I read this. So nice to know that there is yet another reason why breastfeeding is awesome and its great to know that all my hours of expressing and getting breastfeeding established were really worth it.

    Like

    April 22, 2012
    • Awww:) Is your 27 weeker able to suckle? All your work is definitely worth it. Hearing from all these preemie mamas – I’m just amazed by you all – how you roll with it and adapt and do the best you can to get your babies off to a great start in a less than ideal situation.

      Like

      April 23, 2012
      • Emily #

        He is now 5 weeks adjusted, it’s been 18 weeks since he was born, and he is now fully breastfed.

        Like

        April 23, 2012
      • Oh, I misunderstood – thought you meant your baby was 27 weeks and breastfeeding now. Awesome that it is working out for your little guy, and it is nice to know that he’ll reap both short-term and long-term benefits. Best of luck!

        Like

        April 24, 2012
  7. Interesting. I tend to think if the current wisdom on preterm nutritional needs says that breastmilk is not capable of meeting the needs of preterm babies, I question the amount and quality of literature that has actually been done on the subject. It has been shown that in late preterm babies breastmilk is optimal. Pre 32-wks I’m not sure much work has been done. Regardless, it is of course easy to add fortifiers to the breastmilk.

    Growth has long been the gold standard for determining infant development, which has always been a bit puzzling to me. I understand the reasoning behind it, but I think it fails to take into account many factors that we are beginning to see in current research (the content of this article is a great example). I think we will see a lot more results like this in the future.

    Thanks for this article!

    Like

    April 22, 2012
    • I think you are right – that we over-emphasize growth. Clearly we know that “normal growth” can be vastly different from baby to baby, so the reasoning that more growth is always better is flawed. The type of growth is important. For example, in babies grown small for gestational age, catch-up growth is important, but if they catch up in fat and not lean mass, then they are at risk for obesity and metabolic disorders later in life. I think we need to accept a greater range for normal growth and accept that health and development are more nuanced than pounds gained. Thanks for your comment!

      Like

      April 23, 2012
  8. While becoming a lactation educator we spent a lot of time talking about the tools and devices for helping pre-term babies learn to breastfeed. Giving formula was always considered a last resort option. And as far as what is considered normal growth, it is worth understanding where those standards come from. We measure and weigh babies every tens years to come up with those growth charts- so since babies and toddlers are getting bigger (re: adult and childhood obesity) it might be scewing our measurements. Six pound newborns were common 30 years ago- today that might be considered “small.” My pediatrician pulled out a WHO growth chart for me when our son was 3 months old and a nurse had written “kind of small” in chart notes. On that chart he was in the 50th percentile. Normal.

    Anecdotally, I have a dear friend who committed herself to pumping to tube feed her 27 week twins, and went on to successfully breastfeed them for 2 years. Developmentally they were “behind” at 6 months, and at 5 years are “ahead.” (By school placement testing.) She is one of my heros. 🙂 Thanks for the post.

    Like

    April 23, 2012
    • I agree that we are just starting to finally understand what normal growth looks like in breastfed babies. I’m thankful for the WHO growth charts – I think they have cleared up a lot of misunderstanding around growth. I wrote a blog post about it a while back. https://scienceofmom.com/2011/09/26/interpreting-infant-growth-charts/

      And based on this article, I’d say we have a long ways to go in understanding what normal – or optimal – growth looks like in a preemie. I think we have to open-minded about considering that breast milk alone may not be optimal for very pre-term babies, because as I said in the post, breast milk didn’t evolve to nourish a 30-week old baby. But I think we also have to consider the risks that may come with supplementing and accept that a slower growth rate may not be a bad thing. Bigger is not always better. I don’t know why we have this mindset for our little babies, when we turn around a start worrying about obesity by the time our kids are toddlers! My daughter is at the low end of both the CDC and WHO growth charts, but she’s proportional, and I’m glad that I never had an issue with pediatricians questioning the adequacy of breastfeeding for her.

      Like

      April 24, 2012
  9. I’m so happy to have found this article. I’ve been worrying about my little girl’s weight. She was born at 29weeks and has breast milk from her third day of life. She was in the nicu for about 6 weeks. We began breastfeeding after about 3 or 4 weeks. We alternated between breast and bottle once she came of the tube. And after about three weeks home, we breast fed exclusively. She was born weighing 2 lbs 42oz and now at 5.5 months, she’s somewhere between 7-8 lbs. At our last appointment in the beginning of April she weighed 7lbs 4oz, our next appointment is in the beginning of June. I know she has grown a bit because she has grown out of some of her newborn sized clothes but isn’t quite fitting the 0-3 monthsmonths clothes yet. This article has been reassuring. So far my doctor has been very encouraging with the breast feeding and says that she’s growing fine and that I shouldn’t worry. I just hearing stories of moms being told to put their babies on formula because of slow weight grain and my husband and I don’t want to do that if at all possible. So thanks for this article! It’s given me some point of reference.

    Like

    May 15, 2012
  10. Melinda #

    There has never to my knowledge been a prospective double blinded study done showing it save to feed cow milk based formula to any baby much less a sick premature baby. Therefore premature and sick babies should only be be allowed to be given human milk by hospitals unless it is by IRB approved studies. If the babies need fortified breast milk it needs to human milk fortifier not cow milk based. Or just add the nutrients several tImes a day as I did with my breast feeding patients, no big deal. The baby’s don’t need bottles eIther they can cup or finger feed so they don’t get bottle lazy! It’s not niPple confusion, they aren’t at all confused its easier they are smart. Maybe the human milk fortifier will make breast milk marketable for the drug cOmPanies so they can stop push cows milk. Of course this won’t help dairy lobbyist.
    As far as the weight gain, our children are becoming obese. There are no premature WHO breast fed growth charts.
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    Like

    August 4, 2012
  11. I found this page when I was looking for information on weight gain because our child was 31 wks with IUGR to 1.18kg. What I am wondering, and I’d have to check the paper, but when they compared “breast fed” vs not how did they account for a mixed diet with ebm + specialist prem formula? As we all know, sometimes breast isn’t an option, but sometimes volume is the issue not willingness, in those cases a mixed ebm + formula diet would be used and that probably isn’t understood. There is no doubt that ‘breast is best’ but I also note that those babies who are logged as ‘not breast feeding’ perhaps aren’t not getting breast milk either, it could well be more complex.

    Like

    April 12, 2015
    • This is also what I was hoping to find. The quoted study addresses post-hospital fortification by saying that it disrupts breastfeeding and interrupts supply. Is this to say that periodic supplementation with bottle feeds of fortified breast milk (what our NICU is suggesting for our baby post-discharge) are less than optimal because it undermine’s long-term milk supply, eventually leading to early weening and a decrease in the ultimate benefits of breastfeeding?

      Like

      July 1, 2015

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