Musannaf Ibn Abi Shayba 3:3838

Abu Usama narrated to us, from Hisham, from Muhammad, that Aisha said: The Messenger of Allah (peace be upon him) entered upon me while a young girl was with me. He threw his lower garment (izar) to me and said: "Divide it between this young girl and the one who is with Umm Salama, for I do not see them but that they have reached menstruation."