This is one of the most important and commonly asked questions for women performing حج. When Aisha (may Allah be pleased with her) began menstruating during her عمرہ journey, نبی کریم (صلی اللہ علیہ وسلم) told her: 'Do everything that the حاجی does, except do not perform طواف around the House until you are pure.' Based on this, the majority of scholars hold that طواف requires ritual purity and a menstruating woman must wait until her period ends to perform طواف.
The Hanafi school provides an exception for the واجب طواف al-Ifadah: if a woman's travel group is departing and she cannot delay, she may perform طواف 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 طواف after securing protection against discharge and her طواف is valid without penalty — though this is a minority opinion.
Importantly, a menstruating woman remains in احرام and can perform all other حج rituals normally: standing at عرفات, staying at مزدلفہ, stoning at جمرات, سعی (according to some scholars), and making دعا everywhere. She is exempted from the farewell طواف (طواف al-Wada) entirely — this is agreed upon by all scholars. Modern medical options such as medication to delay menstruation should be discussed with a doctor well before the trip.