[Mrs. Don-o]

I'm with you: Some speculative sorts think Jesus came forth as light goes through glass, but who knows how? And there is no explicit doctrine of painless childbirth.

There is an explicit doctrine of Mary's ever-virginity.

This derives its moral significance from the fact that Mary was chaste, and its Christological significance from the fact that she was made pregnant by God and not a man. However it has a third significance: freedom from the rupturing membranes, bleeding and pain indicates freedom from "corruption" in the purely physical sense of deterioration: the tendency toward tearing and strife and pain which accompanies procreation for the female, and is akin to death.

If Christ is reversing the curse of Eve, it makes theological sense that Mary's becoming pregnant and giving birth would be occasions of unalloyed bliss and not of bleeding: the integral opposite of "[tearing] pleasures with rough strife/ Through the iron gates of life."

[RnMomof7]

There is an explicit doctrine of Mary's ever-virginity.

Where does one find scriptural support for that doctrine?

The curse only applies to those born under the curse.. that would mean with original sin ... so was Mary exempt from that curse?