Sahih Muslim
The Book of Menstruation (Kitab Al-Haid)
Book Number: 003 / Hadith Number: 581
Umm Salama reported: While I was lying with the Messenger of Allah (may peace be upon him) in a bed cover I menstruated, so I slipped away and I took up the clothes (which I wore) in menses. Upon this the Messenger of Allah (may peace be upon him) said: Have you menstruated? I said: Yes. He called me and I lay down