Sahih al-Bukhari 6:25
Narrated `Aisha:
Fatima bint Abi Hubaish used to have bleeding in between the periods, so she asked the Prophet (ﷺ) about it. He replied, "The bleeding is from a blood vessel and not the menses. So give up the prayers when the (real) menses begins and when it has finished, take a bath and start praying."
Reference
Sahih al-Bukhari 6:25
In-book reference
Book 6, Hadith 25
Arabic Text
حَدَّثَنَا عَبْدُ اللَّهِ بْنُ مُحَمَّدٍ، قَالَ حَدَّثَنَا سُفْيَانُ، عَنْ هِشَامٍ، عَنْ أَبِيهِ، عَنْ عَائِشَةَ، أَنَّ فَاطِمَةَ بِنْتَ أَبِي حُبَيْشٍ، كَانَتْ تُسْتَحَاضُ فَسَأَلَتِ النَّبِيَّ صلى الله عليه وسلم فَقَالَ " ذَلِكِ عِرْقٌ، وَلَيْسَتْ بِالْحَيْضَةِ، فَإِذَا أَقْبَلَتِ الْحَيْضَةُ فَدَعِي الصَّلاَةَ، وَإِذَا أَدْبَرَتْ فَاغْتَسِلِي وَصَلِّي ".