I am not speaking from a place of expertise, but rather as one also
interested in this topic and who has done some research.

The first consideration with prolactin receptor development is frequency of
feedings/stimulation, which ideally should be *at least* 7-8 times a day for
the first three months postpartum (see discussion of deCarvalho's work in
the brown bible).

A second possibility is that I learned that high levels of androgens--- male
hormones--- can "down-regulate" prolactin and estrogen receptors, so you
might ask and see if anything has changed with mom's overall
health/fertility status.

I am assuming that mom doesn't produce regardless of pump or hand
expression? Because a few people have identified a problem with multi-paras
of nipples that elongate or become meaty over several babies, making good
stimulation and milk removal difficult in the newborn period. Another angle
is age........ how old was she with the first, second, third, etc. baby?

Lisa Marasco, BA, IBCLC