Does a slave woman who bears or is impregnated by her master after he marries her (while she is owned by another) become an Umm Walad upon her subsequent purchase by that man?
General Chapter
Al-Mughni
Book of Freeing Mothers of Children
Primary text
If a man marries another man's slave woman, and she becomes pregnant by him, and subsequently he purchases her or otherwise gains ownership, she does not attain the status of Umm Walad. This applies whether he owned her while she was pregnant or only after she gave birth. This view is held by Al-Shafi'i, based on the reasoning that she was impregnated while belonging to another, thus not establishing the ruling of Istilad (becoming an Umm Walad), similar to if he had committed fornication with her and then purchased her. The default status is slavery, and the exception is only when she is impregnated while in his ownership, based on the consensus of the Companions.
Supporting text
Al-Qadi Ibn Abi Musa narrated from Ahmad that she becomes an Umm Walad in both scenarios (pregnant upon purchase or giving birth in his ownership). This is the position of Al-Hasan and Abu Hanifa, arguing that since she is the mother of his child and he owns her, the ruling of Istilad is established, as in the case where she was impregnated while in his possession. However, this specific narration regarding ownership after birth is disputed in some reports from Ahmad, who expressed reservation in one narration, while others confirm he permitted her sale, stating only Al-Hasan believed she becomes an Umm Walad.