Ibn ’Abbas (RAA) narrated that Allah’s Messenger (ﷺ) said:
“When a man’s slave-woman bears him a child she becomes free at his death.” Related by Ibn Majah and Al-Hakim with a weak chain of narrators.
وَعَنْ اِبْنِ عَبَّاسٍ قَالَ: قَالَ رَسُولُ اَللَّهِ ‏- صلى الله عليه وسلم ‏-{ أَيُّمَا أَمَةٍ وَلَدَتْ مِنْ سَيِّدِهَا, فَهِيَ حُرَّةٌ بَعْدَ مَوْتِهِ } أَخْرَجَهُ اِبْنُ مَاجَهْ, وَالْحَاكِمُ بِإِسْنَادٍ ضَعِيف ٍ 1‏ .‏


‏1 ‏- ضعيف .‏ رواه ابن ماجه (2515)‏، والحاكم (2 / 19)‏.‏

English reference : Book 15, Hadith 1479
Arabic reference : Book 15, Hadith 1435