What are the types of blood that are not considered menstruation?
The answer: I say, and with God's guidance: From the blood of istihada:
1. Blood from outside the womb is not menstruation.
2. Blood before the age of puberty, which is nine years, is not menstruation.
3. Blood coming from the womb due to illness is not menstruation, and if the blood continues, then the flow of some is natural, thus it is menstruation, and the flow of some due to illness is not menstruation; because menstruation and istihada can coexist in one blood at different times, what occurs in ten days has the ruling of menstruation, and what exceeds that is istihada.
4. Blood after the age of menopause is not menstruation. Refer to: 'Umda al-Ri'aya 1: 120, and Sharh al-Wiqaya p.120, and others, and God knows best.