Sunan Ibn Majah, Hadith 629 ⓘ
It was narrated that Asma' bint Abi Bakr said: "The Messenger of Allah was asked about menstrual blood that gets on clothing. He said: 'Rub it off, wash it and perform prayer in (the garment).'"
حَدَّثَنَا أَبُو بَكْرِ بْنُ أَبِي شَيْبَةَ، حَدَّثَنَا أَبُو خَالِدٍ الأَحْمَرُ، عَنْ هِشَامِ بْنِ عُرْوَةَ، عَنْ فَاطِمَةَ بِنْتِ الْمُنْذِرِ، عَنْ أَسْمَاءَ بِنْتِ أَبِي بَكْرٍ الصِّدِّيقِ، قَالَتْ سُئِلَ رَسُولُ اللَّهِ ـ صلى الله عليه وسلم ـ عَنْ دَمِ الْحَيْضِ يَكُونُ فِي الثَّوْبِ قَالَ " اقْرُصِيهِ وَاغْسِلِيهِ وَصَلِّي فِيهِ " .
also referenced under: Book 1, Hadith 672 (In-Book) & Volume 1, Book 1, Hadith 629 (DarusSalam)