Why do pacifiers appear to reduce crib death risk?
Mothers who wish to use a pacifier will very often sleep the baby face-up so that the pacifier stays in place. And face-up sleeping reduces the risk of crib death, because the gases which cause crib death are more dense than air and a baby sleeping face-up is less likely to ingest them. So it is not the pacifier which reduces crib death risk, but rather the statistical likelihood that the baby using the pacifier will be sleeping face-up.
