Musannaf Ibn Abi Shayba 23:190

Mu'tamir narrated to us, from Ayyub, from Abu Qilabah, that a man came to Abu Bakr and said: "I saw in a dream as if I were urinating blood." He said: "I see that you approach your wife while she is menstruating." He said: "Yes." He said: "Then fear Allah."