Dear Maryann, I don't know if someone will have an official research-based
reference, but I can tell you from 30 years exp. in BF field that it is my
impression that moms with fertility problems, difficulty in conceiving etc.
do progress on to problems with supply.  I have no idea what the mechanism
is, but I always figured it was probably hormonally-based.  It could also
be related to her confidence in her body.  Will be interesting to see what
other replys you get.  Sincerely, Pat