Answered by Shaykh Abdul Rahman Al-Kharsa
My menstrual cycle began at night (after 9 PM). Does this night count as the first day of my menstrual period?
Praise be to Allah Most High.
The Start of the Menstrual Cycle
The menstrual cycle begins in Islamic jurisprudence when menstrual blood appears outside the uterus, regardless of whether it happens during the day or night. As soon as the blood is visible, it is considered the start of what is known as a woman’s menstrual period. The count of days and nights is not obligatory; it can also be calculated in hours.
Counting the Menstrual Days
For example, in a situation like yours, you can start counting from the night at nine o’clock until the following night, making it a day and a night. Likewise, on the second day, you start at nine o’clock in the evening, and so on. In this way, you begin your menstrual period at this particular time and finish it at the same time. It’s important to note that the minimum duration for menstruation is three days and their corresponding nights, while the maximum is ten days.
You can also calculate it in hours, with the minimum duration being seventy-two hours, and so on. Imam Haskafi stated, “Its time is established by the emergence of blood, and according to the stronger opinion, the prayers are left during this period. The minimum duration is three days, along with three nights. This addition clarifies the count determined in astronomical hours, meaning it doesn’t need to be nights of those days.” [Haskafi; Al-Dur al-Mukhtar – Kitab al-Hayd]