Rob writes:

'A working mom of a 6 month old told me she seems to be
pumping less milk recently. '

This is normal. I have seen and heard of it happening a great deal.  I have
not seen a lot of academic work on it but based on what *is* out there and
what we already know of the physiology of bf, this is what I think happens
- comments welcome.

when bf is truly well-established  it becomes part of the autocrine system
- it's not dependent on prolactin any more (endocrine) and in most
lactating women prolacatin levels are back to pre-pregnancy levels after
several months of bf. Milk is made in response to the baby's sucking so
most of the milk is made as and when the baby feeds (though there is always
*some* milk there). The baby is truly  expert by now, and the pump's
imitation, second-rate  'sucking action'  just cannot compete with it. When
lactation is linked with prolactin, the pump usually does okay - but as
time goes on, many mothers notice they don't get as much at each session.
It does not mean their supply is going down - though they think it is. It
only means their breasts respond to the baby rather than a plastic thing.
They can try to overcome this by pumping more frequently, and maybe by
double pumping (pumping both breasts at once).  If the baby is happy to bf,
then the mother is likely to be producing the right amount for him when he
feeds.

Heather Welford Neil
NCT bfc Newcastle upon Tyne UK