Sulayman bin Yasar (may Allah have mercy on him) says that a man came to Zayd bin Thabit (may Allah be pleased with him) and said: "My cousin (the daughter of my paternal uncle) declared her slave-girl free upon her own death (i.e., made her mudabbarah), and she has no other property." He said: "Let her take (benefit) from her womb (i.e., her offspring) as long as she is alive."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب المدبر / 21594