A woman whose menstrual cycle has become irregular is confused about her prayer and fasting, so she seeks your guidance?

Question:
Honorable Shaykh, may Allah grant you success, this woman says that she is confused about her prayer and fasting, as she used contraceptive injections, which caused irregularity in her menstrual cycle. Sometimes her period does not come for months, and sometimes menstrual blood comes to her at times other than her known regular time. So in this case, does she rely on the color of the blood? Is what is black and has an odor considered her period, and what is otherwise not considered? Or what does she do? Please guide her, may Allah grant you success.

Answer:
Yes, she relies on the characteristics of menstruation. She relies on the characteristics of menstruation. As long as it has the characteristics of menstruation, such as heat, blackness, and odor, it is not necessary for all three characteristics to be present. If it is foul-smelling, it is menstruation. If it is thick and black, it is menstruation, even if it has only one characteristic.
So she sits out the time of this distinct blood. This is called distinction. She sits out this time. When it ends, she performs the full ritual bath and prays. If it does not have the characteristics of menstruation, and it is just flowing blood, then she does as the scholars mentioned, as in the hadith, that she sits out the majority of menstruation then she performs the full ritual bath and prays.
A woman either sits out her regular time if she remembers it. She sits out the days of her regular time if she remembers it. If she does not remember it, then she sits out the distinct blood if it qualifies as menstruation. She sits out the distinct blood. If there is no distinction, then she sits out the majority of menstruation, six days or seven days. This is what the hadiths regarding the woman with irregular bleeding revolve around. Yes.