Muwatta Imam Malik (Riwayat Ibn al-Qasim)

And with the same chain (it is narrated from Sayyiduna Abu Hurairah, may Allah be pleased with him) that among the women of the tribe of Huzail, one struck the other, causing her to give birth to a stillborn child. Then the Messenger of Allah, peace and blessings be upon him, gave the ruling regarding this that a slave man or slave woman (should be given by the one who struck, as compensation and blood money).