Impressed with your stats background, Wendy! : )
You say: 'As babies also suck in the womb/ suck their thumb clearly they do not always suck to feed. If breastfeeding mothers are told that sucking is always feeding and necessary to build up their supply then they begin to doubt whether their supply is adequate. '
If mothers are told this, without a fuller understanding, then no wonder they get confused. There is a notion that 'nutritive sucking' and 'non-nutritive sucking' are two highly differentiated states. They are not. Sometimes, it is obvious that the baby is enjoying sucking, but not swallowing a lot, and this is pobably NNS. But this can happen in the middle of a 'feed', and then the baby can start to do his NS again! NNS may well have a function in stimulating the breastmilk supply anyway....it certainly has a function in that it's enjoyable for the baby, and mothers can enjoy the peacefulness of it. There will be times when a mother has other things to do, and with confident, well-estabished bf there will be times when she knows she can take the baby off the breast and do these other tnings, without the baby protesting too much. If she wants to faff about with bottles of water to see whether the baby is 'really hungry' then that's her choice ; )
You also say:' If you express milk after feeding you can see if milk was available to the baby. It doesn't tell you if the baby has trouble getting it out but it does mean that you are less likely to worry about an inadequate supply.'
I'm not clear about this at all. Most mothers will get something - even a few drops - out of the breasts on expressing. Are you suggesting that mothers who are worried about their supply express to 'prove' they have milk? I suppose for some mothers it might help - but it is certainly possible to have a poor supply and to be able to express. It's also meaningless to express and 'prove' the existence of milk if the baby can't get it.
You add: ' If you are unable to express then you are no worse off because you were in effect being told your supply was inadequate anyway. '
So it just continues the undermining. A mother can think she has a poor supply, and be quite wrong. You think it would be helpful to be confirmed in a possible misapprehension because she can't express? I knew a mother who exclusively bf twins until six months, and she could never express more than a drop or two - and that was just squeezed out! She did worry about her supply because her twins fed a lot. She expressed because she was so worried - and got a couple of drops. In the end she decided to look at the babies and saw from their growth and development and behaviour that she did indeed have enough.
A mother's milk supply is best judged by looking at the baby. Is he happy, contented, thriving? In the early days, does he have plenty of poos? Are his nappies wet? Does he at least occasionally, come off the breast looking zonked, even if he wants feeding again shortly afterwards?
You say: 'If a pacifier makes a baby more alert....'
Does it? Most pacifiers are given to 'pacify' the baby, not to make them more alert. The study you quoted showed babies who used pacifiers were more alert and less irritable...not that the pacifier made them so, and not that the pacifier could be used therapeutically to waken a sleepy baby so he fed better.
You add: 'perhaps giving one for a few minutes before a feed would be beneficial if the baby is the sleepy type.'
'Perhaps' indeed. Studies? ; )
'The research on adults also suggests other things that may be relevant to frequent feeding'
But babies have to feed frequently to gain weight - to double their birth weight in just a few months, despite having a tummy that is no bigger than the size of the palm of their hand! It's got zip to do with chromium deficiency, surely. Why assume that frequent feeding is pathological?
(I agree with you about the MMR - but that's a different thread. )