It is narrated from Ikrimah (may Allah have mercy on him) that the wife of Sayyiduna Thabit bin Qays (may Allah be pleased with him) obtained khul' from him, and the Prophet (peace and blessings be upon him) fixed "her 'iddah at one menstrual period." This has also been narrated through two other weak chains, and it is not permissible to use the likes of them as evidence.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب العدد / 15598