Eve/Pain during childbirth?

[Sara B]

Why do people continue to believe that the reason women have pain during labor is because Eve commited some sin in the Garden of Eden?

How could it NOT hurt pushing a child's head through your vaginal canal, I mean, seriously? And how could your uterus contracting incredibly hard and fast to open your cervix NOT hurt? That's a huge change in your body in a relatively short period of time.

I guess if Eve would have been a good girl then the act of stretching your cervix to max size and pushing something as large as a child through something as small as a cervix and vagina would actually be pleasurable?

Or are we going by the age old argument that if "she" hadn't commited the sin there would never have been any reproduction? Is this what they actually mean to say?