It is narrated from Hazrat Aisha (may Allah be pleased with her) that Suhailah bint Suhail used to have continuous menstrual bleeding. She came to the Prophet (peace and blessings be upon him) and inquired about this matter. The Prophet (peace and blessings be upon him) instructed her to perform ghusl (ritual bath) at the time of every prayer. But when this became difficult for her, the Prophet (peace and blessings be upon him) instructed her to combine Zuhr and Asr with one ghusl, and to combine Maghrib and Isha with one ghusl, and to perform Fajr with one ghusl.