"Fatimah bint Abi Hubaish said to the Messenger of Allah ﷺ: 'O Messenger of Allah ﷺ, I do not become pure. Should I stop praying?' The Messenger of Allah ﷺ said: 'That is a vein and is not menstruation. When your period comes, stop praying, and when it has passed, then wash the blood from yourself and pray.'"
أَنَّ فَاطِمَةَ بِنْتَ أَبِي حُبَيْشٍ أَتَتْ رَسُولَ اللَّهِ ﷺ فَقَالَتْ يَا رَسُولَ اللَّهِ إِنِّي أُسْتَحَاضُ فَلاَ أَطْهُرُ فَقَالَ رَسُولُ اللَّهِ ﷺ إِنَّمَا ذَلِكِ عِرْقٌ وَلَيْسَتْ بِالْحِيضَةِ فَإِذَا أَقْبَلَتِ الْحِيضَةُ فَأَمْسِكِي عَنِ الصَّلاَةِ وَإِذَا أَدْبَرَتْ فَاغْسِلِي عَنْكِ الدَّمَ وَصَلِّي