Musnad Ahmad 25:1576

Marwan ibn Shuja’ narrated to us, Khasif narrated to me, from ‘Ikrimah, and Mujahid, and ‘Ata’, from Ibn ‘Abbas, who attributed it to the Prophet, may Allah bless him and grant him peace: "The woman experiencing postpartum bleeding and the menstruating woman shall perform ghusl (ritual bath), enter into the state of ihram, and perform all the rites of the pilgrimage, except that she shall not circumambulate the House (the Kaaba) until she becomes pure."