[Machine] Regarding menstruation, if a woman knows the days of her period and then gets divorced but the bleeding continues, she should count the length of her period as three menstrual cycles. When it comes to prayer, if the time of menstruation falls within each month, she should refrain from praying.
عَنِ الْحَسَنِ «فِي الْمُسْتَحَاضَةِ الَّتِي تَعْرِفُ أَيَّامَ حَيْضَتِهَا إِذَا طُلِّقَتْ فَيَطُولُ بِهَا الدَّمُ فَإِنَّهَا تَعْتَدُّ قَدْرَ أَقْرَائِهَا ثَلَاثَ حِيَضٍ وَفِي الصَّلَاةِ إِذَا جَاءَ وَقْتُ الْحَيْضِ فِي كُلِّ شَهْرٍ أَمْسَكَتْ عَنِ الصَّلَاةِ»