Vaginal delivery of human babies includes two often harrowing stages: "Stage 1" consists of "labor" to dilate the cervix, while "Stage 2" encompasses "pushing" the baby out through the vagina.
As far as I have found, the sole purpose of Stage 1 is to dilate the cervix, and this is typically accomplished solely by uterine contractions causing the baby's head to press against it. This seems like a very inefficient mechanism: the cervix begins entirely closed, and the baby's head is somewhat round and about 10cm in diameter. Indeed, debilitatingly painful labor often lasts for many hours.
Balloon dialation devices have been used since the nineteenth century to directly open the cervix during labor. It appears that the current obstetric practice is known as Foley bulb induction. But as far as I have found, such artificial dilation of the cervix is an exceptional measure, not a typical practice. Therefore:
Does artificial dilation assistance (not induction) during Stage 1 labor pose a risk that natural dilation does not?
Does Stage 1 labor have some beneficial function other than to dilate the cervix?