Sunan an-Nasa'i 215
سنن النسائي#215Sahihأَخْبَرَنَا مُحَمَّدُ بْنُ الْمُثَنَّى، حَدَّثَنَا ابْنُ أَبِي عَدِيٍّ، عَنْ مُحَمَّدٍ، - وَهُوَ ابْنُ عَمْرِو بْنِ عَلْقَمَةَ بْنِ وَقَّاصٍ - عَنِ ابْنِ شِهَابٍ، عَنْ عُرْوَةَ بْنِ الزُّبَيْرِ، عَنْ فَاطِمَةَ بِنْتِ أَبِي حُبَيْشٍ، أَنَّهَا كَانَتْ تُسْتَحَاضُ فَقَالَ لَهَا رَسُولُ اللَّهِ صلى الله عليه وسلم " إِذَا كَانَ دَمُ الْحَيْضِ - فَإِنَّهُ دَمٌ أَسْوَدُ يُعْرَفُ - فَأَمْسِكِي عَنِ الصَّلاَةِ فَإِذَا كَانَ الآخَرُ فَتَوَضَّئِي فَإِنَّمَا هُوَ عِرْقٌ " .
It was narrated from Fatimah bint Abi Hubaish that she suffered from Istihadah and the Messenger of Allah (ﷺ) said to her:"If it is menstrual blood then it is blood that is black and recognizable, so stop praying, and if it is other than that then perform Wudu', for it is just a vein
Scholarly Authentication
The label above is the grade most of these scholars gave — one dissenting opinion no longer speaks for all of them. If any scholar calls a narration fabricated, that verdict is shown instead, whatever the others say. Each scholar's own wording:
In-book reference: 1:216