Ibn ‘Umar reported God’s Messenger as saying, “If anyone emancipates a slave who owns property he gets the slave’s property, unless the master stipulates otherwise.”
In the time of God’s Messenger and of Abu Bakr we sold slave women who had borne children, but when ‘Umar was in power he forbade us to do so and we stopped.
Abul Malih told on his father's authority that when a man emancipated a share in a slave, and the matter was mentioned to the Prophet he said, “God has no partner,” and decided chat he should be emancipated.
Ibn ‘Abbas reported the Prophet as saying, “When a man’s slave-woman bears him a child she becomes free at his death.”*
Darimi transmitted it.
* The text has 'au durbur in minhu au ba'dahu’ indicating a doubt on the part of a transmitter as to which words were used. Both expressions amount to the same thing so it seems sufficient to give "at his death" in the translation above.