Istimrar is a continuous flow of blood from a woman following her period.

Rule: If continuous bleeding occurs without any intervening days of purity for 15 days, the calculation is based on her habit of menstruation. That is, beginning with the end of her menstrual period, the duration of purity is considered to be the same as that of the previous month’s and the duration of menstruation is the same as her habit.

Examples:

1. Supposing that a woman’s habit is 25 days of purity and 5 days of menstruation. If she, after remaining free from menstruation for 25 days, sees bleeding that exceeds 10 days and continues to flow thereafter, the length of her previous menstrual period, which was 5 days, will be counted as menstruation, and the remaining days will be counted as istihada (non-menstrual bleeding; bleeding other than menses and postnatal bleeding) because the days of bleeding coincide with the days of menstruation she experienced in the previous month. If blood continues to flow without stopping, of these days of bleeding, 25 days are counted as istihada, and 5 days are counted as menstruation.

EXPLANATION:

She must discontinue salat when she sees blood. When blood is released on the 11th day as well, she should consider it to be istihada. In this case, she should go by the pattern she had in the previous month. She must take a ghusl (purificatory bath) on day 11 [at the completion of day 10], resume salat, and make up the salats that she missed during the days of istihada later on.

2. Supposing that a woman’s habit is 25 days of purity and 5 days of menstruation. After remaining free from menstruation for 25 days, she bleeds for 1 day and does not see blood for 1 day. On the 3rd day, the bleeding restarts, exceeds 10 days, and continues to flow thereafter. In this case, the length of her previous menstrual period, 5 days, is considered menstrual bleeding, and the remaining days are considered istihada, for blood flowed on the first and the last days coinciding with [the time of] her previous period. 1 day of purity in between is treated as if blood flowed on that day as well. If blood continues to flow without stopping, of these days of bleeding, 25 days are counted as istihada, and 5 days are counted as menstruation.

EXPLANATION:

She must discontinue salat when she sees blood. After 1 day of purity, she will resume salat without taking a ghusl. When she bleeds again on the 3rd day, she will discontinue salat. She must take a ghusl on the 11th day [at the completion of day 10], resume salat, and make up the salats that she missed during the days of istihada later on.

3. Supposing a woman’s habit is 25 days of purity and 5 days of menstruation. After remaining free from menstruation for 25 days, she bleeds for 3 days and does not see blood for 2 days. On the 6th day, the bleeding restarts, exceeds 10 days, and continues to flow thereafter. In this case, the first 3 days are considered as menstruation because 3 days of bleeding of this month coincide with the time of her previous period. If blood continues to flow without stopping, of these days of bleeding, 25 days are considered istihada and 5 days are considered menstruation until the bleeding stops.

EXPLANATION:

She must discontinue salat when she sees blood. She must perform a ghusl and resume salat after 3 days of bleeding. Seeing bleeding on the 6th day again, she must discontinue salat. She must take a ghusl on the 11th day [at the completion of day 10], resume salat, and make up the salats that she missed during the days of istihada later on.

4. Supposing a woman’s habit is 25 days of purity and 5 days of menstruation. After remaining free from menstruation for 25 days, she bleeds for 1 day and does not see blood for 2 days and bleeds for 2 days and does not see blood for 2 days. On the 8th day, the bleeding restarts and continues to flow. In this case, the duration of her menstruation is considered 5 days because blood flowed on the first and last days [day 1 and day 5] of menstruation. If blood continues to flow without stopping, of these days of bleeding, 25 days are considered istihada and 5 days are considered menstruation until the bleeding stops.

EXPLANATION:

She must discontinue salat when she sees blood. She must resume it on the 2nd day without performing a ghusl as she is pure of menstruation then. She must discontinue salat again when blood is released on the 4th day. She must take a ghusl on the 11th day [at the completion of day 10], resume salat, and make up the salats that she missed during the days of istihada later on.

5. Supposing that a woman’s habit is 25 days of purity and 5 days of menstruation. After remaining free from menstruation for 25 days, she bleeds for 2 days and does not see blood for 2 days and bleeds for 1 day and does not see blood for 5 days. On the 11th day, the bleeding restarts and then continues to flow. In this case, the duration of her menstrual period does not change. It is still 5 days, for blood flowed on the first and last days of menstruation [day 1 and day 5].

EXPLANATION:

She must discontinue salat when she sees blood. She must resume it on the 3rd day without performing a ghusl. When the bleeding begins again on the 5th day, she must discontinue salat. Afterwards, she must resume it on the 6th day by taking a ghusl and continue it without taking a ghusl on the 11th day, though there is bleeding, because these days of bleeding are counted as istihada as bleeding has exceeded 10 days. She must make up the salats that she missed during the days of istihada later on.

6. Supposing that a woman’s habit is 25 days of purity and 5 days of menstruation. After remaining free from menstruation for 27 days, she bleeds for 3 days and does not see blood for 5 days. On the 9th day, the bleeding begins again and then continues to flow without stopping. In this case, the length of her menstruation is considered 3 days. If bleeding keeps flowing in this way, 27 days of it is considered istihada and 3 days are considered menstruation.

EXPLANATION:

She must discontinue salat when she sees blood. She must resume it after 3 days of bleeding by performing a ghusl but discontinue it again when blood flows on the 9th day. She must resume it on the 11th day [at the completion of day 10] by taking a ghusl and make up the salats that she missed during the days of istihada later on.

7. Supposing a woman’s habit is 25 days of purity and 5 days of menstruation. After remaining free from menstruation for 25 days, she bleeds for 1 day and does not see blood for 1 day and bleeds for 1 day and does not see blood for 1 day. On the 5th day, the bleeding starts again and continues to flow without stopping. In this case, the length of her menstrual period does not change. The first 5 days are considered menstrual, and the remaining days are considered istihada.

EXPLANATION:

She must discontinue salat when she sees blood and resume it on the 2nd day without taking a ghusl. She must discontinue salat again when blood is released on the 3rd day and resume it by performing a ghusl when the bleeding stops on the 4th day. Afterwards, she must discontinue it on the 5th day and resume it on the 11th day [at the completion of day 10] by performing a ghusl. She will make up the salats that she missed during the days of istihada later on.