“The birth happened to her [the Virgin Mary] exactly as to other women, consciously with her mind functioning normally and with the parts of her body helping along, as is proper at the time of birth, in order that she should be his normal natural mother and he her natural normal son. For this reason her body did not abandon its natural functions which belong to childbirth, except that shes gave birth without sin, without shame, without pain, and without injury, just as she had conceived without sin. The curse of Eve, which reads: ‘In pain you shall bear your children’, did not apply to her. In other respects things happened to her exactly as they happen to any woman giving birth. For grace does not destroy or impede nature and nature’s works; indeed grace improves and promotes them.”
Martin Luther. ‘The Gospel for Christmas Eve’ from the Christmas Postil. Luther’s Works, American Edition, vol. 52. (Philadelphia: Fortress Press, 1974), p. 11-12.