If a woman starts menstruating or has post-partum bleeding before performing Tawaaf Al-Ifaadhah (circumambulation):

She should remain in Makkah until she becomes pure and perform Tawaaf at her convenience, even if the month of Thul-Hijjah has ended, for the Tawaaf Al-Ifaadhah has no specific time according to the right opinion, and her company should wait for her until she completes the ceremonies of her Hajj. This is based on what is proven in an authentic Hadeeth (narration) that Safiyyah started menstruating during the Farewell Hajj; thereupon the Messenger of Allah said: “Is she going to detain us?” It was said to him, “She has descended (to Makkah) and performed Tawaaf around the House (i.e. Tawaaf Al-Ifaadhah), O Messenger of Allah.” On that the Prophet said: “Then, let her depart (with us).” [Muslim]

This indicates that if a woman menstruates before performing Tawaaf Al-Ifaadhah, she has to remain there and those of her Mahrams (non-marriageable men) as she needs have also to remain with her until she gets clean and performs Tawaaf. That is the basic rule; but if she cannot wait due to unavoidable circumstances, like running out of money, lack of company, or the like, in this case, she may return home without performing Tawaaf. But she should remain in a state of partial Ihraam (for she has only partially dissolved her Ihraam), which means that all things become lawful for her save sexual intercourse.

Once she purifies herself, she should return (to Makkah) and perform Tawaaf. But if it is difficult for her to return due to the unbearable cost or trouble, like the one who lives in a distant country and can neither return easily nor delay her departure: in this case, she may make Ghusl (ritual bath) and tightly wrap herself (in a piece of absorbent cloth), and perform Tawaaf around the House, and nothing is due on her. This is the preferred opinion of Shaykh Al-Islam Ibn Taymiyyah and his disciple Ibn Al-Qayyim .

But if she menstruates and nothing of the acts of Hajj remain due on her other than that she has not performed the Farewell Tawaaf, then she may leave and nothing would be due on her, and her Hajj is valid, based on the previous Hadeeth of Safiyyah and the statement of Ibn ‘Abbaas “The people were commanded to make (Tawaaf round) the House the last thing they do (before departure), but this task has been lightened for the menstruating woman.”

     If a pilgrim completes all rites of Hajj due on him save Tawaaf Al-Ifaadhah, and he would like to leave Makkah and return home:

In this case, a single Tawaaf would suffice him for both Ifaadhah and Farewell, provided that he should intend to perform thereby either Tawaaf Al-Ifaadhah of Hajj or both together, for what is intended by the Farewell Tawaaf is to make (Tawaaf around) the House the last thing to do (before departure). But if he intends only the Farewell Tawaaf, it would not suffice him for Tawaaf Al-Ifaadhah, for Tawaaf Al-Ifaadhah is a pillar of Hajj whereas the Farewell Tawaaf is only an obligation, and the pillar is superior, and in no way can the inferior be sufficient for the superior.

     If a pilgrim could not throw the pebbles during the daytime due to the severe crowds, or his being engaged in something that did not give him the opportunity to throw until sunset:

In this case, he may throw at night and nothing is due on him, since some scholars made it permissible to throw at night with no restriction.

     A pilgrim may be have some valid excuses that do not allow him to spend the length of time obligatory on him in Mina, which is, according to the majority of scholars, most of the night:

A typical example is that if a pilgrim heads towards Mina to spend the night there, and then was delayed because of crowds or the like, and could not arrive there except very late at night; in this case, nothing would be due on him, since the delay was not intentional, nor was he negligent in that respect, but rather he has done as much effort as lies within his capacity to arrive there as soon as he could. Allah The Almighty Says (what means): {Allah does not charge a soul except [with that within] its capacity…..} [Quran 2:286]

The Prophet gave a concession to Al-‘Abbaas to spend the nights of Mina in Makkah, to be able to take care of his water supplies. He also gave concession to the camel herds to spend the night outside Mina. Scholars joined with them those for whom it is difficult to spend the night there, like the one who is sick or taking care of a sick person whom he fears to leave, or has property and fears its loss, and so on.

These are some situations which a pilgrim might be exposed to during his Hajj. There are many others which we have not mentioned here, for they are mentioned elsewhere in the Hajj section; and Allah Knows best.