This is one of the most important and commonly asked questions for women performing الحج. When Aisha (رضي الله عن her) began menstruating during her العمرة journey, النبي (صلى الله عليه وسلم) told her: 'Do everything that the الحاج does, except do not perform الطواف around the House until you are pure.' Based on this, the majority of scholars hold that الطواف requires ritual purity and a menstruating woman must wait until her period ends to perform الطواف.
The Hanafi school provides an exception for the واجب الطواف al-Ifadah: if a woman's travel group is departing and she cannot delay, she may perform الطواف al-Ifadah while menstruating, but must sacrifice a camel (badanah) as a penalty. Some contemporary scholars, including Shaykh Ibn Taymiyyah, held that if a woman has no choice (her group is leaving, she cannot stay), she may perform الطواف after securing protection against discharge and her الطواف is valid without penalty — though this is a minority opinion.
Importantly, a menstruating woman remains in الإحرام and can perform all other الحج rituals normally: standing at عرفة, staying at مزدلفة, stoning at الجمرات, السعي (عند some scholars), and making دعاء everywhere. She is exempted from the farewell الطواف (الطواف al-Wada) entirely — this is agreed upon by all scholars. Modern medical options such as الأدوية to delay menstruation should be discussed with a doctor well before the trip.