I was at the conference in Melbourne last weekend when Peter Hartmann
presented and cast fore/hind milk into doubt, plus I have heard him talk on
this topic before. Apologies Peter if this is not as erudite, but this is
how I understand it.

His reseach shows that about 70% of the fat content in milk samples is
related to the degree of emptying of the breast (ie lower fat when there is
a higher residual volume, and vice versa).  If the mother has a small
capacity breast which the baby drains every feed, then the fat content will
tend to increase along a continuum as the feed progresses (like fore and
hind milk).  However Peter Hartmann's work on milk synthesis has clearly
established that not only are all mothers different, but all breasts are
different!

He has taken measurements of breast volume over 24 hours with a computerised
breast-cam.  The difference between max volume and min volume during the 24
hours equals "breast capacity" - ie the maximum amount of milk that breast
can hold.  Most women have noticeable capacity differences between right and
left.  The range of "normal" includes breasts which have a small capacity
and are emptied after every feed, and large capacity breasts which can be
500mls plus.  Obviously the baby will not empty this volume and because milk
is left in the breast the rate of synthesis will be low. Eg 500mls, baby
takes 100mls, 400mls left, synthesise 40 mls = 440, baby takes 120, 320
left, etc.  By the end of the day the baby may be draining the breast and
her synthesis rate will be faster.

Since fat content is determined mostly by degree of emptying, with the
latter breast the baby will not get much fat until later in the day, whereas
with the former breast the baby will get fat-rich milk every feed.  Peter
Hartmann's work shows that breast capacity (which is very variable) is not
related to milk volume per 24 hours or fat content per 24 hours as long as
the baby has unrestricted access to the breast.

The clinical implication (as I see it) is to allow unrestriced and untimed
breastfeeding and trust the baby and the breasts to work it out between them
as nature intended.  Don't mess with a good system and don't put too much
emphasis on concepts such as fore/hind milk when every baby and each of the
two breasts performs differently.

Personally, I think we are kidding ourselves when we try to play around with
increasing fat intake because it probably averages out over 24 hours anyway.
As I understand it, the baby's appetite is regulated by fat intake and
individual babies manage to keep their 24-hour fat intake fairly constant to
their needs despite different daily patterns.  I acknowledge that this may
go wrong when feed intervals are spaced out (eg by pacifiers) or the baby
does not "finish the first breast first" - assuming finish does not
necessarily mean empty.

Message for the day:  All breasts are different

Ros Escott     [log in to unmask]


Ros Escott    ( Tasmania, Australia)
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