Hi, Anne Perry and everyone!
It's always nice to think of you all even when we don't have time to say much!
But Anne Perry's post caught our attention and we couldn't resist a comment...

This sounds very much like a baby who has found that biting up into the
breast actually does (in this case) give a reward - another milk ejection
reflex! The description indicates that the baby does this to start the feed
and again later to trigger another flow of milk - OUCH!! Then when the milk
flows, the baby is too busy to maintain the "bite", needing to concentrate
on drinking rather than drowning. This is not necessarily the reason for the
nipple blanching - this baby could well have developed a few other exotic
habits too. (We've seen babies who don't bite up into the breast but who use
just their tongues (somehow!) to apply exquisite amounts of pressure on the
nipple - causes blanching+++! We don't see these cases as vasospasm - just
the result of having the blood vessels in the nipple squashed enough so that
no blood can flow into them. (But we also don't see how you can know for
certain if it's this pressure problem or vasospasm if it happens in the
baby's mouth - you can't watch it happening.)

"Biting" does not itself cause nipple damage unless the baby "bites" at the
moment the nipple is between the gums. It more usually causes PAIN (!)
around the areola and bruising there. But of course to achieve a really
catastrophic "bite" you need to have your toungue retracted - and then you
can do some seriously nasty damage to a nipple in your mouth! Like
blistering and sandpapering!

We think vasospasm happens after and between feeds - one moment the nipple
looks perfectly OK and the next it has quite spontaneously blanched. We
always associate this situation with babies who are causing some sort of
nipple trauma. (Meaning we have seen a lot of it and NEVER in any other
context - so we think that the nipple trauma is responsible for the
vasospasm, which is why it stops happening after the nipples are healed and
the baby is no longer doing appalling things at the breast.)

The other interesting link-up we've made is that if a mother is suffering
from breast pain that hits her suddenly between feeds, asking her to quickly
check the nipple on that breast shows that the nipple has blanched at the
same time. As the pain in the breast subsides, you can watch the blood
returning to the nipple.
This would seem to be further evidence that breast pain in women whose
babies are still a pain to feed (a pain in the nipples, that is) is linked
to unhappy nerve endings in the nipple. (So to speak!)

Robyn Noble and Anne Bovey, Brisbane, Australia