Source: Fatāwā Arkān al-Islām
❖ Question
A woman is fasting, and just 10 minutes (or even less) before sunset, her menstruation (ḥayḍ) begins.
➊ Is she allowed to break her fast immediately, or should she wait until sunset?
➋ Will the fast of that day be considered valid?
➌ Is it necessary to make up missed fasts immediately after Eid, or can they be delayed throughout the year?
❖ Answer
الحمد لله، والصلاة والسلام على رسول الله، أما بعد!
➊ The Fast Breaks as Soon as Menstruation Begins
◈ If menstruation begins even a few minutes before sunset, the fast is rendered invalid immediately.
◈ After the fast is nullified, she is permitted to eat and drink, whether she does so immediately or later — that is her choice.
◈ Since the fast has been invalidated due to menstruation, it is obligatory upon her to make it up (qaḍāʼ).
➋ The Fast Will Not Be Counted
◈ The number of minutes before sunset does not hold any significance in this case.
◈ As per Shar‘ī principle, menstruation and fasting cannot coexist — even if it starts moments before sunset.
◈ Therefore, the fast of that day will not be accepted and must be made up.
➌ When to Make Up the Missed Fast?
◈ It is narrated from ʿĀʾishah (رضي الله عنها) that she would make up missed Ramadan fasts in the month of Shaʿbān:
❀ "ʿĀʾishah (RA) would make up her missed Ramadan fasts in Shaʿbān."
(Reported in Mishkāt, etc.)
◈ This shows that delaying the makeup fasts until later months is permissible.
◈ However, it is recommended to make up fasts as soon as possible, due to the uncertainty of life.
◈ Delaying without reason may result in a person dying while still liable for those missed fasts.
وَبِاللّٰہِ التَّوفِیق
And Allah is the source of all success.