It is narrated from Tawus that Umar bin Khattab (may Allah be pleased with him) said: "Is there anyone who has heard anything from the Prophet ﷺ regarding the fetus?" Then Haml bin Malik bin Nabighah (may Allah be pleased with him) stood up and said: "I was living with my two co-wives when one of them struck the other with a tent pole, causing her to miscarry a dead child. In this matter, the Messenger of Allah ﷺ ruled for a slave or a slave-girl." Then Umar (may Allah be pleased with him) said: "If we had not heard this, we would have given a different verdict in this case."
Hadith Referenceمسند الإمام الشافعي / كتاب القتل والقصاص والديات والقسامة / 1652