970 — Ibn ʿUmar (may Allah be pleased with them both) said: “The divorce of a slave-woman is effected by two pronouncements, and her waiting period is two menstrual cycles.” Al-Daraqutni narrated it and also transmitted it as a marfūʿ report, declaring the latter weak (1). Abū Dāwūd, al-Tirmidhī, and Ibn Mājah likewise recorded it on the authority of ʿĀʾishah. Al-Ḥākim ruled it sound, but the other scholars disagreed with him and unanimously judged it weak (2).

— Ḥadith grading —
The report is weak (ḍaʿīf ) and mawqūf.
The author explains: Al-Daraqutni narrated it mawqūf from Ibn ʿUmar and ruled that version sound, but he also related it marfūʿ; that chain contains ʿAṭiyyah al-ʿAwfī, whom several leading critics declared weak. Abū Dāwūd, al-Tirmidhī, and Ibn Mājah transmitted it from ʿĀʾishah, yet that isnād passes through Muẓāhir ibn Muslim. Abū Ḥātim said of him, “his ḥadith is munkar,” while Ibn Maʿīn said, “he is unknown.” Although al-Ḥākim deemed the report sound, the scholars overruled him and agreed that it is weak; therefore it cannot be used as evidence.

— Points gleaned from the ḥadiths —
1 – The umm al-walad mentioned in ḥadith 968 is a slave-girl who has conceived by her master and given birth to a child that possesses recognisable human features, even if faint.
In terms of service and marital enjoyment she is treated like an ordinary slave-woman, whereas with respect to the transfer of ownership she is treated like a free woman. Thus it is lawful to have intercourse with her, benefit from her labour, or hire out her services, but it is not permissible to sell her, give her away, dedicate her as an endowment, or engage in any other transaction that transfers—or leads to the transfer of—ownership, such as pledging her in mortgage.