What is the ruling about a woman who menstruates continuously?
According to the Hanafi school, a woman who experiences incessant bleeding has three conditions:
1- Menstruation of a girl who bleeds before reaching puberty and sees blood continuously also after reaching puberty is accepted as having menstruation for ten days in every month, and her cleanliness is accepted as twenty days. So, ten days of a month is accepted as menstruation period while remaining twenty days of it is accepted as istihadha.
2- A woman who experiences incessant bleeding after having menstruation regularly and remembers her menstruation in the past (mu’tadah) takes as basis her menstruation in her previous condition of menstruation and cleanliness. In other words, if she used to experience five days of menstruation and twenty days of cleanliness previously, she continues the same way. Therefore, she accepts five days of every month as menstruation period and twenty days of every month as cleanliness period.
3- When it comes to the woman who experiences incessant bleeding after having menstruation regularly and does not remember her menstruation in the past (mutahayyirah); it cannot be judged whether such woman is in period of menstruation or cleanliness. She needs to be cautious about religious judgments, which means that she cannot enter masjid, recite the Qur’an, or have sexual intercourse; she performs ghusl for each prayer time separately and establishes her prayer in this way (Zaylai, Tabyin, I, 62-63). The dominant opinion of the Shafi’i school regarding mutahayyirah women is also in this direction (Shirbini, Mughni al-muhtaj, I, 181).
According to the Maliki school, if a mutahayyirah woman can discriminate menstrual bleeding by its odor, color, change in its solidity, or having pain, that is deemed as menstrual bleeding. Therefore, she is accepted in her menstruation period in these days and as istihadha in other days (Dasuqi, Hashiyah, I, 171).
According to the Hanbali school, if a mutahayyirah woman forgets both the time and the number of days of menstruation or forgets the number of days although she remembers its time, her menstruation is considered as six or seven days for every month. She identifies if it is six or seven days by considering menstruation of herself or her relatives by prevailing opinion. She is accepted as having bleeding other than menstruation in the other days. If she remembers the number of duration of her menstruation but forgets its time, she accepts the days in the beginning of each hijri month as the days of her menstruation while other days are accepted as istihadha for her (Ibn Qudamah, al-Mughni, I, 403-403).
Consequently, there is no hardship for the women in the first and second conditions to determine their menstruation and cleanliness days. However, it is clear that both mutahayyirah woman and her family will face some hardships if she acts by the views of Hanafi or Shafi’i schools. In this respect, such women may act in line with the opinions of Hanbali and Maliki schools. These women act by being subject to the excused (istihadha) judgments in the days accepted as period of cleanliness.
Notwithstanding that the judgments in the sources of Islamic law are as mentioned above, today one may benefit from the diagnoses of expert doctors in order to eliminate hesitations on whether the bleeding is menstrual or not.
Source: Presidency Of Religious Affairs The Turkey, High Board of Religious Affairs FATWAS