In my experience, women in the hospital barf a whole lot more than women in home births. It makes perfect sense! Women in the hospital are starved! Women in the hospital have hypoglycemia which causes nausea which brings on vomiting. Women at home are encouraged to eat to hunger, even if it is simply nibbling. Those women who aren't very hungry are nudged towards eating something because they start to complain of nausea. Once they have eaten something, miraculously, their nausea disappears.
Do women who eat in labor throw up? Sure. Do women who don't eat not throw up? Sure.
But, by far, I see it as a definite cause and effect of no food = nausea/vomiting. (I also know I would much rather throw something up than nothing. But that's just me.)
That doctors continue saying digestion stops in labor is absurd. Oh, that's right, MIDWIVES say that, too! A local midwife just said that this week here! It might slow. But stop? C'mon. Why would it stop? Does elimination? No. Doctors have a vested interest in keeping women NPO (nothing by mouth) - they are easier/safer to anesthetize that way (supposedly). Why a midwife would want a woman to not eat is beyond me.
I believe doctors who continue the old saw that women in labor shouldn't eat simply have no experience with women who have. Just like a lot of other things like women who walk or squat or not have IVs or moan or or or.
Rise up and eat women! Barf no more.