Sayyiduna Ibn Abbas (may Allah be pleased with them both) reports: The Prophet (peace and blessings be upon him) said regarding a woman in menstruation or postnatal bleeding: "She should perform ghusl (ritual bath) and enter into ihram, and perform all the rites of Hajj except for the circumambulation (tawaf) of the House (Ka'bah). Then when she becomes pure, she should perform this tawaf as well."
Related hadith on this topic