If a woman’s bleeding stops before ten days and she deems it probable that there is blood inside, she must either perform ritual acts of worship as a precautionary measure or perform istibrāʾ; and it is not permitted for her to refrain from worshipping without performing istibrāʾ.
Istibrāʾ here means she must insert some cotton inside the vagina and wait for a short while – and if her habit is such that her bleeding stops for a short while in the middle of ḥayḍ, as it has been said of some women, she must wait for a longer time – then, she must bring the cotton out.
If it is clean, she must perform ghusl and perform her ritual acts of worship; and if it is not clean – even if it is stained with a yellow-coloured liquid – then, in the event that she does not have a habit of ḥayḍ, or her habit is ten days, or the days of her habit have not yet finished, she must wait. If her bleeding stops before ten days, she must perform ghusl; and if her bleeding stops on the tenth day or her bleeding lasts for more than ten days, she must perform ghusl on the tenth day.
If her habit is less than ten days, then in case she knows that her bleeding will stop before the completion of ten days or on the tenth day, she must not perform ghusl.