عَنْ أَبِي سَعِيدٍ الْخُدْرِيِّ رَضِيَ اللَّهُ عَنْهُ قَالَ كُنَّا نَبِيعُ أُمَّهَاتِ الْأَوْلَادِ عَلَى عَهْدِ رَسُولِ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَآلِهِ وَسَلَّمَ
It is narrated from Sayyiduna Abu Sa'id Khudri (may Allah be pleased with him), he says: In the time of the Messenger of Allah (peace and blessings be upon him), we used to sell ummahat al-awlad (slave women who had borne children to their masters).