Apologies for my late reply to these posts,I've been away and its taking a
while to catch up.
>One thing that I have puzzled over frequently is if plasma
>prolactin level doesn't play a role in the regulation of the rate of milk
>synthesis in the longer term (ie after the first few weeks post partum) why
>does metoclopramide and domperidone (which result in an increase in plasma
>prolactin) result in an increase in milk production? Does anyone know?
As prolactin is now considered a permissive hormone once lactation is
established, rather than having a direct effect on milk volumes, it is
probable that there is a threshold level that is required for lactation to
be maintained. It is possible that these galactogogues can raise prolactin
levels to the required threshold if plasma prolactin is low.
If plasma prolactin is normal (most often the case I suspect although nobody
seems to check these levels prior to treatment) but supply is low, it is
possible that the prolactin receptors are either not efficient enough or not
numerous enough to respond appropriately. It is possible that when we see
an increase in these mothers' supply when treated with Motilium etc, that it
is stimulating the prolactin receptors to either increase or be more
effective. But this is pure hypothesis, perhaps the increase in supply has
nothing to do with the galactogogue but would have occurred naturally with
time. We need a double blind case control study. There are no studies
looking at pre and post plasma prolactin levels and milk production - an
area ripe for research!
>It was found that milk production remained constant over the first six
>months of the child's life. Does this mean that milk consumption remained
>the same? What does this mean for the concept of growth spurts and
>increasing supply thereto.
Recent respondents confirmed that this has been found to be correct.
Consequently it does now become difficult to attribute unsettled behaviour
and frequent feedings to growth spurts requiring an increase in volume of
feeds. Leon Mitoulis, who has done recent research on fat in breast milk,
has found a sudden drop and then a rebound increase in fat levels at around
4-6 weeks. So those people who posted about changes in fat content being
responsible may be very close to the truth.
>My question to this is, how often and by what method was the caloric content of
mother's milk studied? The same mother over time? How can the content of
milk be tested when the fat content thus the caloric content changes so
much: from the beginning of a feeding to the end of a feeding, over the age
of a baby, the time of day, and so on and so forth. Even what a baby gets
from the breast by nursing (and does the baby squeeze the breast?) must vary
from what a mother gets from the pump (compression and suction vs. merely
suction). I don't understand how there can even be an average.
There can be an average - but you are right, only for individual mothers and
their individual breasts at a given time in their lactation
In the following research:
Mitoulis LR Sheriff Hartmann PE. 2000. Short and long term variation in the
production, content, and composition of human milk fat. IN: Short and Long
Term Effects of Breastfeeding on Child health. Ed. Koletzko et al. Kluwer
Academic/Plenum Publishers. pp401-402.
Leon measured fore and hind milk samples from every feed (each feed being
every time the baby went on one breast), from each breast over 24 hour
periods at 1, 2, 4, 6, 9 and 12 months lactation. Milk production was also
measured. He emphasised the importance of rigorous sampling methods in order
to measure accurate fat content and that fatty acid composition and average
fat contents quoted in the literature are virtually useless if milk
production is not taken into account. His research (not yet published but
has been presented) also confirmed that concentrations of constituents of
individual mothers milk is not related to growth (but like prolactin I'm
sure there is a required threshold) but volume is correlated to growth.
Some things continue to be a mystery! Perhaps our bodies are so smart that
they know exactly how much energy to produce in one mother's milk to meet
the metabolic needs of that mother's particular baby at any given time of
that babies growth. We know that fatty acid composition in milk changes in
relation to development of the baby's nervous system so perhaps this idea is
not too far fetched.
Regards
Cathy Fetherston RM MSc IBCLC
Perth Western Australia
***********************************************
The LACTNET mailing list is powered by L-Soft's renowned
LISTSERV(R) list management software together with L-Soft's LSMTP(TM)
mailer for lightning fast mail delivery. For more information, go to:
http://www.lsoft.com/LISTSERV-powered.html
|
