Ghusl for Menstruation and Postpartum
Man Lā Yaḥḍuruh al-Faqīh|Volume 1|Book 1|Chapter 21
وَقَالَ أَمِيرُ اَلْمُؤْمِنِينَ عَلَيْهِ اَلسَّلاَمُ: «فِي اِمْرَأَةٍ اِدَّعَتْ أَنَّهَا حَاضَتْ فِي شَهْرٍ وَاحِدٍ ثَلاَثَ حِيَضٍ إِنَّهُ تُسْأَلُ نِسْوَةٌ مِنْ بِطَانَتِهَا هَلْ كَانَ حَيْضُهَا فِيمَا مَضَى عَلَى مَا اِدَّعَتْ فَإِنْ شَهِدْنَ صُدِّقَتْ وَ إِلاَّ فَهِيَ كَاذِبَةٌ.
The Commander of the Faithful Imam Ali ibn Abi Talib عليه السلام said regarding a woman who claimed to have experienced three menstrual cycles in one month: 'Women from her close circle (those familiar with her cycle) should be asked whether her previous menstruation followed the pattern She claims. If they testify in her favour, She is to be believed; otherwise, She is considered lying.'
- Ṣaḥīḥ al-Faqīh