Musnad Ahmad 626:15

Abu Sa'id narrated to us, Za'idah narrated to us, Mansur narrated to us, from Ibrahim, from 'Ubayd ibn Nadilah, from al-Mughirah ibn Shu'bah: That a woman struck another woman with a tent pole, killing her while she was pregnant. She was brought to the Prophet, peace and blessings of Allah be upon him, and the Messenger of Allah, peace and blessings of Allah be upon him, judged regarding her that the blood money (diyah) be paid by the paternal relatives ('asabah) of the killer, and for the fetus, a ghurra (a slave). Her paternal relatives said: "Shall we pay for one who did not eat, nor drink, nor cry out, and whose like would be considered void?" He said: "Rhyming like the rhyming of the Bedouins." And Shu'bah said: I heard 'Ubayd.