Musannaf Ibn Abi Shayba 9:1592

Abu Bakr ibn Ayyash narrated to us, from Aslam al-Minqari, from Abdullah ibn Ubayd ibn Umayr, who said: Abdur Rahman ibn Awf sold a slave girl whom he had had intercourse with before he had ensured she was not pregnant (istibra'). She then manifested a pregnancy while with the one who had purchased her. He disputed with him before Umar. Umar said, "Did you have intercourse with her?" He said, "Yes." He said, "And you sold her before you ensured she was not pregnant?" He said, "Yes." He said, "You were not worthy of that." He said: So he summoned the physiognomists (al-qafah), and they looked at him and attributed the child to him. He said: So many children were born to him from her, and they did not reproach him for it.