Urwah bin al-Zubayr (may Allah have mercy on him) narrates that Mughirah bin Shu'bah (may Allah be pleased with him) said: Umar (may Allah be pleased with him) consulted them about imlas al-mar'ah (the case of a woman struck so that she miscarries her unborn child). Mughirah (may Allah be pleased with him) said: "The Messenger of Allah (peace and blessings be upon him) decided a slave (ghurrah) in it." Umar (may Allah be pleased with him) said: "If you are truthful, then bring someone who knows this." So Muhammad bin Maslamah (may Allah be pleased with him) testified that he had heard the Messenger of Allah (peace and blessings be upon him) decide a slave (ghurrah) in it.
Hadith Referenceالمعجم الكبير للطبراني / باب الميم / 18193