If a woman has two consequent periods with regularity in...

If a woman has two consequent periods with regularity in time of their occurance and duration, then she is a zatu 'l‑'adah = a woman who has formed a fix­ed pattern for her monthly periods. On the other hand, if a zatu 'l‑'adah woman discovers that her fixed pattern for menstruation has changed and this happens for two consequent months, then she should follow the new pattern. The zatu 'l‑'adah women can be of three types: (a) a woman whose periods occur at a fixed time and for a fixed…