The World Federation One Stop Fiqh

Ruling 1608

If a woman’s ḥayḍ or nifās stops before the time of ṣubḥ prayers in the month of Ramadan but she does not have time to perform ghusl, she must perform tayammum; however, it is not necessary for her to remain awake until the time of ṣubḥ prayers. The rule is the same for a junub in the event that his duty is to perform tayammum.