Abdullah bin Shaddad narrates from Maymunah (may Allah be pleased with her) that the Messenger of Allah (peace and blessings be upon him) used to pray while I was beside him (peace and blessings be upon him), even though I was menstruating, and sometimes his (peace and blessings be upon him) garment would touch me when he (peace and blessings be upon him) prostrated; and he (peace and blessings be upon him) used to pray on a small mat.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصلاة / 5225