Also, a careful reading of Genesis 3:16 indicates that Eve MIGHT have already experienced childbirth (to "multiply" the pain suggests that she might have had unpainful or less painful childbirth). However, most believe that Cain and Abel were the first children and they certainly seem to have been born after the Fall.
Yeah, there’s a lot of misconceptions about the account of the fall, and there is absolutely nothing that indicates how much time elapsed between Adam’s creation and Eve’s and Eve’s creation and the Fall.
I always figured that God’s was simply commenting that the pain in childbirth would be greatly increased, only notifying them of that fact. It implies that there would have been some pain in childbirth anyway, just not as much.
When the mechanics of it are considered, it’s inconceivable that childbirth would have been pain free completely.
I would say that Cain and Abel were born after the fall as they had a sin nature otherwise, they would not have been offering sacrifices nor would Cain have murdered Abel.