Musannaf Ibn Abi Shayba 19:740

Abu Bakr narrated to us, he said: Abu Mu'awiyah narrated to us, from al-A'mash, from Abu Sufyan, from his elders, that a woman whose husband was absent became pregnant, so he [the husband] brought her to Umar. He [Umar] ordered her to be stoned. Mu'adh said: "If you have a way against her, you have no way against what is in her womb." Umar said: "Detain her until she gives birth." She gave birth to a boy who had two front teeth. When his father saw him, he said: "My son." When that reached Umar, he said: "Women are incapable of bearing the likes of Mu'adh. Were it not for Mu'adh, Umar would have perished."