Sahih Muslim Book 003, Hadith Number 0587.
Chapter : The menstruating woman is permitted to wash the head of her husband, comb his hair, and her left-over is clean, and one is permitted to recline in her lap and recite the Qur'an.
'Aisha reported: The Messenger of Allah (may peace be upon him) said to me: Get me the mat from the mosque. I said: I am menstruating. Upon this he remarked: Your menstruation is not in your hand.