POSSIBLE THEORIES FOR BAA
Either at the start of your journey at birthor start of breastfeeding. This could be due to having a complicated birth, being separated from baby, having a preterm baby, having tongue tie issues, or (very commonly) the pain from incorrect positioning and attachment.
Studies show women going through nipple pain are also experiencing high emotional distress (see here) - no surprise there - but what does this mean for infant feeding, 5, 6, 10, 20 times a day? Severe discomfort and, understandably, an aversion toward that activity.
Even once the pain has subsided the memory is still there, and the dynamic of the relationship may continue on the trajectory upon which is was started, which is not all together healthy and loving in the sense that it is a pleasant and enjoyable and rewarding activity for the mother, or infant. Cells also carry a 'memory of pain', which may explain chronic discomfort or pain at the breast, even after issues are resolved, see here for an article on a study that shows this. With pain at the beginning of any relationship, the stage is set, and it is very difficult to change the story path. Not impossible, but difficult.
FEEDING ON DEMAND
Extended feeding, into toddlerhood, and beyond, could be one of the reaons for BAA to occur in some women. The time the infant spends at the breast varies for women, but mothers often express the feeling of being 'touched out' and needing some physical space and time away from feeding. This is a complex arena and would need much more research and thought. More information will be added in due course, if you want to contribute please contact me here.
Cortisol - see here about cortisol
It is a theory of mine (pure conjecture at the moment but hey, most theories start that way), that women who experience BAA have higher levels of 'stress' hormone cortisol than women who do not. This, in turn, is responded to by the infant, (as cortisol can pass through breastmilk), who then increases the frequency of suckling at the breast, which in turn again raises levels of cortisol in the mother due to her having the aversion and agitation while breastfeeding. If you're not flooded with the loving feeling oxytocin gives you, it is also possible that milk ejection is compromised, as oxytocin is linked to the release of milk, see here. A study looking at blood cortisol and oxytocin levels would either confirm or refute this, but there are yet to be any clinical study trials on BAA . We should campaign for it, I already am, but research costs a lot of money, and other things take priority.