>
>> Karen, it is known that nursing during the night produces more prolactin
>> than day-time nursing, so it's quite possible that the night time
>> co-sleeping and nursing helps keep the prolactin levels high and therefore
>> helps keep milk production going.
>>
>Kathy, this makes perfect sense until you factor in the transfer fron
>endocrine to autocrine control.  How big a factor is prolactin
>at the six month  mark?
>

We need to remember that the endocrine/autocrine distinction is a *theory*
about breast milk production, not a proven fact, and that some studies of
prolactin levels do not show the decrease at 3-4 months -- perhaps because
these are moms who are nursing on cue/demand throughout day and night (third
world mothers).  I suspect that at least *some* of the decrease in prolactin
noted in some studies of western women is due to a concerted effort on the
mother's part, even if unconscious, to get the baby onto a 3-4 hour
schedule.  Where babies are truly allowed to nurse on demand, they follow a
more physiological pattern for a species with breast milk composition like
ours, of nursing several times an HOUR, around the clock.  Among women in
some highland New Guinea tribes, even the 3-4 year olds are nursing several
times an hour, all day long.  I am not saying that I don't *believe* the
endocrine/autocrine theory, just that all the evidence is not in yet, and I
think a lot of people don't have a proper respect for the role of culture
(scheduling) in affecting biology.

Katherine A. Dettwyler, Ph.D.
Associate Professor of Anthropology and Nutrition
Texas A&M University