What is the ruling on prayer when there is intermittent bleeding after taking an injection to stop conception for one year, given that menstruation was expected to cease completely?

The blood a woman sees is considered menses if it occurs at a time suitable for menstruation. If it stops, ghusl (ritual bath) and prayer become obligatory if its duration has reached a day and a night, or if it has stopped according to the Maliki school. If the blood returns after fifteen days or more, it is a new menstrual period. If the interval is less than that, and the total of the two bleeding periods and the days in between does not exceed fifteen days, then it is all considered menses. However, if the blood returns after less than fifteen days, and the total of the two bleeding periods exceeds fifteen days, then the woman is in a state of istihadah (prolonged vaginal bleeding outside of menstruation). She should abstain from prayer and fasting only during the days of her usual period. Any bleeding beyond that is istihadah, which necessitates performing wudu (ablution) for each prayer after its time has begun, while taking precautions.