“As the Son has been given to us without a father, so the Child has been born without a birth. As the Virgin herself did not know how the body that received divinity was formed in her own body, so neither did she notice the birth. Even the prophet Isaiah affirms that her giving birth was without pain, when he says: “Before the pangs of birth arrived, a male child came forth and was born” (Is 66:7).
Therefore, he was chosen to introduce a twofold innovation into the order of nature, since he did not begin to exist because of sin, nor was he born in pain. This happened for an understandable reason; there is nothing absurd about it. Just as she who introduced death into nature by her sin was condemned to bear children in suffering and travail, it was necessary that the Mother of life, after having conceived in joy, should give birth in joy as well. No wonder that the angel said to her, “Rejoice, O full of grace!” (Lk 1:28). With these words he took from her the burden of that sorrow which, from the beginning of creation, had been imposed on birth because of sin.”Gregory of Nyssa ,On the Song of Songs 13; PG 44, 1052 D-1053 B
Gambero, L., 1999. Mary and the Fathers of the Church 1st ed. Translated by Buffer, T., San Francisco: Ignatius Press. p. 153.