Coach Smith here again.

Yes, there's an outlet for milk in the breast. But not for edema in the
breast nor edema in an injured ankle. Engorgement is edema PLUS milk stasis.
Two different processes.

In the breast, edema is most likely to happen in the early days postpartum,
when the whole physiology of lactation triggers profound changes in
circulation, milk synthesis, fluid dynamics, etc in the breast tissues. BTW,
edema happens in cows, too, especially first-time mothers. It's almost as if
all the extra fluid that collected around the mom's ankles during pregnancy
goes running up to the breast to see what's going on. [Thanks to Martha
Grodrian (Brower] for that analogy). Edema is generally easy to recognize
and short in duration.  AFTER the initial edema response is passed, warmth
can facilitate circulation or healing.

Milk stasis is another thing. Milk stasis left unrelieved can result in
edema. Great early breastfeeding management, as we're hearing from our
colleagues in England, eliminates much of the milk stasis and therefore much
of the edema. Simple milk stasis (without edema) is usually relieved by
ordinary mechanical methods - baby nursing and/or pumping. Thermal
applications are probably unnecessary in either case. If heat or cold appear
to help, I agree with Jan - let's officially study this in a situation of
simple milk stasis without edema. I bet we won't find any difference between
heat vs. cold, or thermal treatments vs Scotch vs. a backrub.

But back to edema. Heat makes edema worse, which will automatically make
milk stasis worse. Before recommending a thermal treatment for full breasts,
decide whether you're dealing with milk stasis, or milk stasis PLUS edema. I
maintain my position: don't put heat on edema in the breast or elsewhere in
the body.

Linda J. Smith, BSE, FACCE, IBCLC
Bright Future Lactation Resource Centre
Dayton, OH USA
http://www.bflrc.com