What should a menstruating woman do from the meeqaat until the end of Hajj?
Question

What should a woman do if her period comes at the beginning of the days of Hajj before she enters Makkah?.
Praise be to Allah.If a menstruating woman passes the meeqaat and intends to enter ihram from the meeqaat, then when she reaches Makkah she should do all the actions of Hajj except for tawaf around the House and Sa`i between al-Safa and al-Marwah, which she should delay until she becomes pure. This is also what a woman should do if her period comes after she enters ihram and before she does tawaf. 
But if her period comes after doing tawaf, then she may do Sa`i between al-Safa and al-Marwah even if she is menstruating.  
The scholars of the Standing Committee were asked: 
What is the ruling on a menstruating woman doing Hajj? 
They replied: 
A menstruating woman is allowed to do Hajj. The one who enters ihram has to do all the actions of Hajj, but she should not circumambulate the House until her period ends and she does ghusl. The same applies to women who are bleeding following childbirth. If they do all the essential parts of Hajj then their Hajj is valid. 
Fatawa al-Lajnah al-Daa’imah li’l-Buhooth al-‘Ilmiyyah wa’l-Ifta’, 11/172-173. 
Shaykh Muhammad ibn Saalih al-‘Uthaymeen said: 
If a woman intends to do ‘umrah, it is not permissible for her to pass the meeqaat without entering ihram, even if she is menstruating. So she should enter ihram even if she is menstruating and her ihram is valid. The evidence for that is the fact that Asma’ bint ‘Umays, the wife of Abu Bakr (may Allah be pleased with them both) gave birth, when the Prophet (peace and blessings of Allah be upon him) was camped at Dhu’l-Hulayfah on his way to perform the Farewell Pilgrimage. She sent word to the Prophet (peace and blessings of Allah be upon him) asking him what she should do. He said: “Do ghusl and tie a piece of cloth around yourself and enter ihram.” 
The blood of menstruation is like the blood of nifaas. So we say to the menstruating woman: if she passes the meeqaat and she intends to do ‘Umrah or Hajj, we say to her: Do ghusl, tie a piece of cloth around yourself and enter ihram. What is meant by tying a piece of cloth is placing a piece of cloth over the vagina and tying it in place, then entering ihram whether for Hajj or ‘Umrah. But when she enters ihram and reaches Makkah, she should not go to the Ka’bah or circumambulate it until she becomes pure. Hence the Prophet (peace and blessings of Allah be upon him) said to ‘Aa’ishah, when she menstruated during ‘umrah: “Do everything that the pilgrims do, but do not circumambulate the House until you become pure.” This report was narrated by al-Bukhaari and Muslim. According to Saheeh al-Bukhaari ‘Aa’ishah stated that when she became pure she circumambulated the House and did Sa`i between al-Safa and al-Marwah. This indicates that if a woman enters ihram for Hajj or ‘Umrah when she is menstruating, or her period comes before she does tawaf, then she should not do tawaf or Sa`i until she becomes pure and does ghusl. But if she did tawaf when she was pure and after she finished tawaf her period came, then she should continue and do Sa`i even if she is menstruating, and she should cut her hair and end her ‘umrah, because tahaarah (purity) is not essential for Sa`i between al-Safa and al-Marwah. 
Sittoon Su’aalan fi’l-Hayd, question no. 54. 
And Allah knows best.