Caution: Translations of Quran and Ḥadīth may lead to possible misapplications and misinterpretations. This site is intended for students of sacred knowledge that are proficient in comprehending classical Arabic and have a strong foundation in Islamic sciences. Also note that religious injunctions rely on several aspects beyond what one may glean through reading individual aḥādīth.
darimi:859Muḥammad b. ʿĪsá > Hushaym > Yūnus > al-Ḥasan > Tumsik al-Marʾah

[Machine] Regarding prayer during menstruation, if a woman becomes clean before the seventh day, then she may perform the prayer, otherwise, she should refrain from praying until she becomes clean. However, if she becomes clean before the tenth day, then she may perform the prayer. If not, she should wash herself, perform ablution, and then pray while in a state of istihadah (minor ritual impurity).  

الدارمي:٨٥٩أَخْبَرَنَا مُحَمَّدُ بْنُ عِيسَى حَدَّثَنَا هُشَيْمٌ حَدَّثَنَا يُونُسُ عَنِ الْحَسَنِ قَالَ «تُمْسِكُ الْمَرْأَةُ

عَنِ الصَّلَاةِ فِي حَيْضِهَا سَبْعًا فَإِنْ طَهُرَتْ فَذَاكَ وَإِلَّا أَمْسَكَتْ مَا بَيْنَهَا وَبَيْنَ الْعَشْرِ فَإِنْ طَهُرَتْ فَذَاكَ وَإِلَّا اغْتَسَلَتْ وَصَلَّتْ وَهِيَ مُسْتَحَاضَةٌ»