Teresa, are you asking about the distinction between endocrine and autocrine
control of lactation?  I understand this as being (brief description)
related to the fact that the initiation of lactation is driven by a cascade
of hormonal events.  The abrupt decline in estrogen and progesterone and the
removal of the blocking factor of Prolactin Inhibitory Factor all occur when
the placenta is fully delivered.  This generally triggers lactogenesis II
within 2-6 days whether there is any infant suckling or not.  Even  in
societies with colostrum taboos or among moms who deliver still-birthed
babies, the milk will "come in" because this is an automatic sequalea of the
end of pregnancy.

Clearly, nipple stimulation can hasten the onset of lactogenesis II.
Conversely, lack of it can delay onset past the norm of 72 hrs.  The
stimulation of the nipple, which produces releases of prolactin and
oxytocin, is connected with milk release and milk production on an on-going
basis.  But there are a lot of other complex interactions going on with
other hormones  (like human growth factor, insulin, androgens, etc.) that
can interfer or assist in the endocrine control of lactation.

 On an on-going basis, maintenance of lactation is linked closely to how
much milk is removed on a 24 hr basis.  This is called autocrine control. I
suspect that while endocrine control predominates in the first few weeks
postpartum and autocrine control predominates in established lactation,
there is always an interplay between both forms of control.  As an example,
another pregnancy will interfer with supply no matter how much the older
baby tries to keep removing milk.   The work from Dr. Hartmann's lab is the
place to go to understand control of milk production.  There have been
several papers in JHL elucidating this, and we review them and this process
(with ref citations) in The Breastfeeding Atlas.

I think it is tricky to generalize about infant crying.   Infants who are
compromised in some aspect of how much milk they are able to remove probably
cry more.  They are hungrier babies because they understimulate milk
production and are stuck for the long haul (unless assisted) with a milk
supply that rather quickly calibrates to an inadequate level of production
to meet their needs.  They may also consume less hind milk than a more
robust baby due to fatigue issues.

Any theory of crying would have to factor in the enormous number of subtle
variables.  I've seen very ineptly feeding babies cry all day when not at
breast, yet while "nursing", are really just sleeping with the nipple in
their mouths.  They get just enough CCK to pacify themselves, but never
enough calories to grow well or feel full and content.  So while it's
certainly good to respond with more holding, one also wants to emphasize
assessing the underlying reasons for the baby's distress.  I think it is
impt. to rule out hunger and organic illness that hasn't fully manifested,
birth injury, significant reflux (which is characterized by poor growth),
sensory defensiveness, etc.  I have seen several children with what turned
out to be bowel rotations or herniated intestines who cried all the time and
were just miserable, but the defect was a while in being identified.

There is an interesting guy named Phillip Zeskind, PhD, who has spoken at
ILCA confs. (papers in 1994 ILCA conf. syllabus)  before.  He studies infant
crying.  He feels that spectral analysis of infant crying "may reflect the
integrity of nervous system function, even when the infant appears to be
healthy by routine pediatric measures...[and tries to] understand how
variations in the sound of crying associated with the infant at risk may
affect the perceptions of parents and caregivers... and understand how the
bidirectional interactions between the infant's health status and the
parent's response to the infant lead to different developmental outcomes
including child abuse, poor intellectual development and learning
disabilities."    He developed what he calls a "ponderal index."  This is a
way of trying to identify and measure pre-natal effects  (materal illness,
maternal stress, maternal substance abuse) that may, in essence, pre-dispose
an infant to more early crying due to prenatal affect on the developing
nervous system.  His papers are very interesting and may help your effort:

Crowe H, Zeskind P:  Psychophysiological and perceptual responses to infant
cries varying in pitch:  comparison of adults with low and high scores on
the child abuse potential inventory.  Child Abuse and Neglect 1992;
16:19-29.

Zeskind P and Marshall R:  The relation between mother's perceptions and
pitch of infant crying,  Child Dev 1988; 26:321-333.

Zeskind P:  Behavioral dimensions and cry sounds of infants of differential
fetal growth,  Infant Behavior and Devel 1981; 4L321-330.


Barbara Wilson-Clay, BS, IBCLC
Austin Lactation Associates
LactNews Press
www.lactnews.com

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