Safiyyah bint Abi Ubayd (may Allah have mercy on her) said that Sayyiduna Umar bin al-Khattab (may Allah be pleased with him) said: What is the matter with men who have relations with their slave women and then leave them to go out? Then a slave woman comes to me whose master acknowledges having had relations with her; I will attach the child to him. So after this, either let your slave women go out or keep them back.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب اللعان / 15375