The World Federation One Stop Fiqh

Ruling 506

If a woman’s nifās stops and she deems it probable that there is blood inside, she must either perform ghusl as a precautionary measure and ritual acts of worship, or she must perform istibrāʾ; and it is not permitted for her to refrain from performing ritual acts of worship without performing istibrāʾ. The method of performing istibrāʾ was mentioned in Ruling 495.