Musannaf Ibn Abi Shayba 9:906

Al-Fadl ibn Dukayn narrated to us, from Hammad ibn Salamah, from Hakim al-Athram, from Abu Tamimah al-Hujaymi, from Abu Hurayrah, who said: "Whoever approaches a menstruating woman or a woman in her anus has disbelieved in what was revealed to Muhammad."