Sahih Bukhari | Volume 1 | Hadith Number 376

Narrated 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).