Musnad Ahmad 626:3

'Abd al-Razzaq narrated to us, Ibn Jurayj informed us, Hisham narrated to me, from 'Urwah ibn al-Zubayr, that he narrated from al-Mughirah ibn Shu'bah, from 'Umar, that he consulted them regarding the *imlas* (miscarriage) of a woman. Al-Mughirah said to him: "The Messenger of Allah, may Allah bless him and grant him peace, decreed for it a *ghurrah* (a slave/compensation)." 'Umar said to him: "If you are truthful, then bring someone who knows that." So Muhammad ibn Maslamah testified that the Messenger of Allah, may Allah bless him and grant him peace, had decreed it.