Sahih Bukhari Volume 1, Book 8, Hadith Number 376

Narated By ‘Abdullah bin Shaddad : Maimuna said, “Allah’s Apostle was praying while I was in my menses, sitting beside him and sometimes his clothes would touch me during his prostration.” Maimuna added, “He prayed on a Khumra (a small mat sufficient just for the face and the hands while prostrating during prayers).