Urwah bin al-Zubayr (may Allah have mercy on him) narrates from Mughirah bin Shu'bah (may Allah be pleased with him) that Umar (may Allah be pleased with him) consulted them about imlas al-mar'ah. Mughirah (may Allah be pleased with him) said: I said to Umar (may Allah be pleased with him): "The Messenger of Allah (peace and blessings be upon him) decided a ghurrah in it." Umar (may Allah be pleased with him) said: "If you are truthful, then bring me someone who knows this along with you." So Muhammad bin Maslamah (may Allah be pleased with him) said: "I witnessed the Prophet (peace and blessings be upon him) decide a ghurrah in the case of imlas al-mar'ah." So Umar (may Allah be pleased with him) decided accordingly.
Hadith Referenceالمعجم الكبير للطبراني / باب الميم / 18199