In a message dated 96-07-30 10:32:48 EDT, you write:
<< A friend of mine, who is breastfeeding a 1 month old, has been having
numbness in her breast extending into her chest while she feeds her son. >>
Julie,
I would tend to think this is letdown sensations or milk ejection reflex
(MER).  This is often described as "pins and needles" which is often how we
refer to numbness.  Did mom have any breast surgery, biopsy, or injury?
Laurie Wheeler, Rnc, Mn, Ibclc