Hadith 1105B2

قَالَ مَالِكٌ : وَإِنِ اشْتَرَاهَا وَهِيَ حَامِلٌ مِنْهُ، ثُمَّ وَضَعَتْ عِنْدَهُ، كَانَتْ أُمَّ وَلَدِهِ بِذَلِكَ الْحَمْلِ، فِيمَا نُرَى وَاللَّهُ أَعْلَمُ
Imam Malik, may Allah have mercy on him, said: And if (the husband) buys her (the slave woman) in such a state that she has already become pregnant from his semen, then if she gives birth to a child after coming into his ownership, according to our opinion, she will be considered Umm Walad because of that pregnancy. And Allah knows best.
Hadith Reference موطا امام مالك رواية يحييٰ / كتاب النكاح / 1105B2
Hadith Takhrij «فواد عبدالباقي نمبر: 28 - كِتَابُ النِّكَاحِ-ح: 32»