Lady Aisha Siddiqa (may Allah be pleased with her) narrates: Fatima bint Abi Jash submitted: O Messenger of Allah! I do not become pure, so should I leave the prayer? Lady Aisha (may Allah be pleased with her) narrates: The Prophet (peace and blessings of Allah be upon him) said: This is from another vein, it is not menstruation. When menstruation comes, then leave the prayer, and when its duration passes from you (i.e., the specific days of menstruation are over), then wash the blood from your body and start performing the prayer.
Hadith Referenceصحیح ابن حبان / كتاب الطهارة / 1350
Hadith Gradingفضيلة الشيخ الإمام محمد ناصر الدين الألبانيصحيح - «الصحيحة» (301)، «صحيح أبي داود» (281): ق.فضيلة الشيخ العلّامة شُعيب الأرناؤوطإسناده صحيح على شرطهما.