Musannaf Ibn Abi Shayba 1:1223

'Abd al-Samad ibn 'Abd al-Warith narrated to us, from Hisham al-Dastawa'i, from Hammad, from Ibrahim, who said: "Four do not recite the Qur'an: at the time of relieving oneself, at the time of sexual intercourse, the person in a state of major ritual impurity (junub), and the menstruating woman. Except for the person in a state of major ritual impurity and the menstruating woman, for they may recite the verse and what is similar to it."