Sayyidah Aishah (may Allah be pleased with her) said: The Messenger of Allah (peace and blessings be upon him) mentioned Safiyyah bint Huyayy (may Allah be pleased with her), and it was said that she had begun menstruating. The Messenger of Allah (peace and blessings be upon him) said: "Perhaps she is going to hold us back." It was said: She has performed the ifadah. He (peace and blessings be upon him) said: "Then no." Urwah (may Allah have mercy on him) said: Sayyidah Aishah (may Allah be pleased with her) said: We mention this; if it did not benefit them, why would people send their women ahead? And if it were as he says, there would have been more than six thousand menstruating women at Mina, all of whom had performed the ifadah.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الحج / 9754