A menstruating woman is required to delay Tawaf al-Ifadah (also called Tawaf al-Ziyarah) until her menstruation ends and she has performed ghusl. This is because purity is a condition for the validity of Tawaf according to the majority of scholars. There is no fixed deadline for performing Tawaf al-Ifadah — it can be performed at any time after the standing at Arafat, even if delayed by days or weeks.
Sheikh Ibn Baz explained that when a woman menstruates before performing Tawaf al-Ifadah, she completes all other rites of Hajj — stoning, sacrifice, cutting hair — and remains in a state of partial ihram. In this state, everything becomes permissible for her except marital relations with her husband. This partial ihram continues until she becomes pure, performs ghusl, and completes Tawaf al-Ifadah. Once she performs the Tawaf, full tahallul (exit from ihram) is complete.
Sheikh Ibn Uthaymeen stated that the woman should wait patiently in Makkah until she is pure, if possible. If her travel group must leave, she has several options: she may stay behind with a mahram and join the group later; she may travel home and return later to perform the Tawaf; or, in cases of extreme hardship where returning is not possible, some scholars (following the position of Ibn Taymiyyah) permit her to perform Tawaf with menstruation as a last resort, wearing protection. However, the stronger position is that she must wait.