Lillian
asked: “I learned in the CLC course that there is no such thing as foremilk and
hindmilk for changes in nutritional content. I have also read and heard from
IBCLCs that hind milk has a higher fat and calorie count with less lactose
compared to foremilk. I am also aware that some cultures who nurse more
frequently than the US culture of 8-12x/day would not necessarily “empty” the breast
or access the hindmilk. These cultures still produce healthy and typical kids.
The foremilk/hindmilk concept has come up regarding pumping mothers in the NICU
where weight increase has been an issue at my place of work. However, the
regiment an IBCLC recommended seemed very tedious. Additionally, I know the
nutritional content of preterm breastmilk is different than term breastmilk and is
baby specific for that feeding dyad. Would you be able to point me in a
positive direction to further understand if foremilk and hindmilk differences
exist and how this may impact the breastfeeding dyad or if this is a myth?”
So let’s dive right in with a discussion about the
differences between foremilk and hind milk.
It is absolutely NOT A MYTH.
I am not surprised when I hear people tell me that they doubt there is a
difference in breastmilk from the beginning to the end of the feeding, I used
to say the same thing. “What? Is there
some kind of barrier that is removed half way through the feeding?” I am a little embarrassed to admit I said
that to many a patient over the early years of my career. Well there is plenty of evidence to suggest
that there is a difference between the milk released at the beginning of the
feed and that released at the end of the feed.
The primary difference is in the fat content. The difference is so very striking and
predictable that it is a common scientific method of measuring the amount of
milk remaining in the breast, the method is called “The Creamatocrit Method”. The group that uses this method the most is
the Hartmann group out of Australia. If
you pull any study from that group regarding milk volume you will find
reference to that well documented phenomenon.
My favorite article on the basics is Kent, 2007 “How breastfeeding
works” published in The Journal of Midwifery and Women’s Health 52(6). It is older and doesn’t go into detail about
the MER, but it is a straightforward discussion on most clinical breastfeeding
questions. It is easy to understand if
you think of simple fluid dynamics. If
you mix sand and water in a pail allow it to settle and then start pouring, the
first thing that will come out is the water, as you get to the end of the
bucket you will get more sand and eventually, it will be wet sand that comes
out and very little water. The same is
said for breast milk. The first milk
ejection (MER) reflex is almost entirely water and lactose, I describe it as
“skim milk” or “fat free milk” It is approximately 4% fat. The second MER is like whole fat milk, mostly
water, but more fat. The third MER is a
milk shake, whole fat milk and high fat ice cream, and the last is almost entirely
fatty ice cream, a little more than 12% fat.
In that study they cite another Hartmann lab study: “Kent JC, Mitoulas
LR, Cregan MD, Ramsay DT, Doherty DA, Hartmann PE. Volume and frequency of
breastfeeds and fat content of breast milk throughout the day. Pediatrics
2006;117:e387–95” here they document the findings specifically. If you are interested in a full discussion,
that is probably where you should start.
For reference values, Khan, Prime, Hartmann and few others did an
interesting study looking at 24-hour nutrient intake for the Journal of Human
lactation in 2013 (Volume 29(1)) where they used the fore milk and hind milk
samples of mothers to extrapolate an average fat, lactose, and protein content
of each feeding and the test weights of the infant and calculated the 24-hour
intakes. They, again demonstrated that
the milk was lower in fat before the feeds (average 32 g/L) and higher after
the feed at 56 g/L. They found no
difference in the lactose or the protein in the foremilk and hindmilk samples. All that said, the authors also point out
that the average baby tends to balance out feedings and that there is no real
difference from feeding to feeding when you look at 24-hour intakes. So you could say that there is very little
clinical value in looking at foremilk/hindmilk as a phenomenon for the average
baby. Of course, it isn’t “the average
baby” that a lactation consultant sees.
We are the experts of infant feeding and are usually only called on when
there is a problem. A baby who isn’t
growing well, has green frothy poop, and eats for less than 10 minutes at a
feeding, has all the hallmarks of a baby eating a low-fat diet due to
inadequate time spent on the breast.
That is where a firm understanding of the difference between foremilk and
hindmilk will be most valuable.
As
for feeding preterm infants. I don’t
have much experience in that topic, but what knowledge I do have comes from the
excellent work of Paula Meier. A decent
review of breastfeeding management written by her is Meier, Write, and Engstrum
(2013) Management of Breastfeeding During and after the Maternity
Hospitalization for Late Preterm Infants. Clinics in Perinatology; 40, 689–705. It is a good over view of the entire feeding
problem for preterm infants. While I was
putting this note together, I also found a very promising review from Meier,
Johnson, Patel, and Rossman, published in Clinics in Perinatology 2017; volume
44 (1) pg 1-22. It is called “Evidence
Based methods that promote human milk feeding of preterm infants: An expert
review. It looks very promising, but I
don’t have time to read it before I send you this email. I advise you to pull it and look into it.
I
hope that helps and answers a few questions for you.
