In the beginning of my menstruation, a brown fluid comes out for a period of four days and after that normal blood comes out for a period of eight days. I don’t know what to do about the first days: are they considered menstruation (ḥayḍ) or not? May Allah reward you with goodness.
Answer: (Sheikh Muḥammad Shuqeir)
The entire period of time is menstruation, because the maximum time for menstruation is fifteen days.
What is the ruling when a girl has constant bleeding, and does it nullify her fast?
Answer (Imam Muḥammad Saʿīd Ramaḍān al-Būṭī):
If a woman or girl suffers from bleeding that causes confusion regarding the start and finish of her monthly cycle and other days of bleeding then she must rely on whatever her normal habit was, what she knows from herself, before she was afflicted with this illness. For example, if her monthly cycle at that time was the first ten days of every month, now she must consider the first ten days of every month to be days of menstruation (ḥayḍ), and therefore in those days she is not allowed to pray, fast, recite the Qurʾān etc. Once those days have passed, she washes and resumes her praying and her other acts of worship and the blood that she sees after that is considered abnormal bleeding (istiḥāḍah) due to illness.
[Translated from Maʿ an-Nās: Mashūrāt wa Fatāwa (Damascus: Dār al-Fikr, 1427/2006), p.25]