It is narrated from Sayyiduna al-Mughirah bin Shu'bah (may Allah be pleased with him) that Sayyiduna Umar (may Allah be pleased with him) consulted the people about the fetus that a woman miscarries, and al-Mughirah (may Allah be pleased with him) said: "The Messenger of Allah (peace and blessings be upon him) judged in it with (the payment of) a male or female slave (ghurrah)." Sayyiduna Umar (may Allah be pleased with him) said: If you are truthful, bring someone who will testify along with you. So Sayyiduna Muhammad bin Maslamah (may Allah be pleased with him) testified that he had heard the Messenger of Allah (peace and blessings be upon him) give this very judgement.
Hadith Referenceالمعجم الكبير للطبراني / باب الميم / 16556