On the contrary, Augustine says (Serm. de Nativ. [Supposititious), addressing himself to the Virgin-Mother: “In conceiving thou wast all pure, in giving birth thou wast without pain.”
I answer that, The pains of childbirth are caused by the infant opening the passage from the womb. Now it has been said above (28, 2, Replies to objections), that Christ came forth from the closed womb of His Mother, and, consequently, without opening the passage. Consequently there was no pain in that birth, as neither was there any corruption; on the contrary, there was much joy therein for that God-Man “was born into the world,” according to Isaiah 35:1-2: “Like the lily, it shall bud forth and blossom, and shall rejoice with joy and praise.”
Reply to Objection 1. The pains of childbirth in the woman follow from the mingling of the sexes. Wherefore (Genesis 3:16) after the words, “in sorrow shalt thou bring forth children,” the following are added: “and thou shalt be under thy husband’s power.” But, as Augustine says (Serm. de Assumpt. B. Virg., [Supposititious), from this sentence we must exclude the Virgin-Mother of God; who, “because she conceived Christ without the defilement of sin, and without the stain of sexual mingling, therefore did she bring Him forth without pain, without violation of her virginal integrity, without detriment to the purity of her maidenhood.” Christ, indeed, suffered death, but through His own spontaneous desire, in order to atone for us, not as a necessary result of that sentence, for He was not a debtor unto death.