What constitutes irregular bleeding that extends beyond the maximum duration of menstruation (Istihada)?

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If the irregular bleeding exceeds the customary length of menstruation, it is treated as Istihada (abnormal, non-menstrual bleeding). In such a case, she does not refrain from religious duties beyond the duration of her established habit under any circumstances. For example, if her habit is three days and she sees five days of blood, or sees blood extending over two periods, or sees more or less than her habit, she refrains only for the length of her established habit. This is based on the prophetic instruction to sit for the duration her menses usually detained her, and because she has an established habit to which she reverts, similar to a woman experiencing Istihada.