Is it permissible to fast the six days of Shawwal after making up for the missed days of Ramadan, knowing that menstruation will prevent the completion of the six days of fasting?

One who begins fasting the six days of Shawwal, then menstruates before completing them, and her menstruation does not cease until after Shawwal ends, should fast the remaining days in Dhu al-Qi'dah, and it is hoped that she will attain their reward.