What is the ruling on the prayer and fasting of a woman who takes birth control pills, and bleeds almost every day, knowing that her period was previously regular, and that she is not convinced by the idea of prayer and fasting in this situation, and she wonders why there is no clear and specific fatwa on this issue, and why the questioner is asked to adopt the fatwa that he believes is the most correct, and what is the extent of the validity of her prayer and fasting if she is mistaken in determining the period of menstruation from irregular bleeding (istihada)?

If the blood exceeds fifteen days, then the woman is in a state of istihadah (non-menstrual vaginal bleeding). She must determine the duration of her menstruation based on her previous habit. If there is no previous habit, then she should differentiate between the types of blood. Otherwise, she should estimate it as six or seven days. The woman in istihadah must perform ablution (wudu') for each prayer after its time has begun, and she may pray with this ablution as many obligatory and supererogatory prayers as she wishes. She has all the rulings of pure women during the period of istihadah.