Sayyidah Khawlah bint Hakim (may Allah be pleased with her) narrates: I said: O Messenger of Allah! I menstruate, and I have only one garment. The Prophet (peace and blessings be upon him) said: Wash it and pray in it. I said: O Messenger of Allah! The trace of blood will remain after that. The Prophet (peace and blessings be upon him) said: It will not harm you. Imam al-Tabarani recorded this narration in al-Mu'jam al-Kabir; its chain contains a narrator, al-Wazi' bin Nafi', and he is da'if (weak).
Hadith Referenceمجمع الزوائد ومنبع الفوائد / كتاب الطهارة / 1555