In a message Anne wrote:

<<Baby sometimes nurses just fine, but other times she pulls off screaming and
pulls in her legs as soon as she has started to swallow the milk. 'Like the
milk hurts her stomach'. The baby is totally unpredictable as to when it does
this.>>

I've seen babies do this when their gums hurt "teething", not hungry but needs
the comfort of sucking. To assess this possibility, try rubbing gums with a
clean finger or ice cube wrapped in a washcloth and see what happens.

Deb