Many many thanks to all who replied to my question.  More responses will be
very welcome too!
I should have said I had tried to find what I wanted in the archives and
really wanted to read what is known right now, as well as what I found by
browsing through the past few years.
Dee, your post was really really helpful with its comments on the
variability of mothers' responses even to retained placental fragments!
It seems there are two distinct issues here: one is whether progestin can
reduce an already existing milk supply, and the other is whether progestin
given immediately after birth can prevent the milk from coming in in the
first place, through some such mechanism of interfering with the
receptivity of the milk-making cells to prolactin because the body does not
sense the postpartum drop in progesterone -- i.e. through a different route
than the drop in supply experienced by some mothers who take progestin
weeks later.
I get a very clear answer to the first: some mothers (anecdotally, and it
would be really really nice if there were some published case studies I
could refer to...) do indeed experience a drop in their milk supply even
with progestin-only contraceptives.
The second question seems harder to answer.  Basically most of you gave
evidence which bears on the first question.  Whether or not a Depo shot in
the first 12 hours or so really does prevent the establishment of a milk
supply in some mothers, by a mechanism which is specific to postpartum
hormonal *changes*, seems to still be in the realm of "it makes sense that
it might".

On the other hand there is no doubt in my mind that giving Depo at any time
to a breastfeeding mother is a very poor idea!  I was struck by Mary Kay's
point that new mothers given a Depo-Provera shot are very likely to get
pregnant 3 months later because they haven't followed up with further
shots.  Given the contraceptive effects of exclusive breastfeeding, it
would seem that counseling them on the LAM might actually yield better
contraceptive results.

Now, is it okay if I compile excerpts from your various posts, with just
your initials and credentials, for the doctor I have been discussing this
with? If any of you is uncomfortable with that, write to me and I will take
your post out of the bundle.

Elise
LLLL, IBCLC
Bath (Swiftwater) New Hampshire USA

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