The inquirer says that his wife uses contraceptive pills. Each month she takes 21 pills, stops and has her menses. She wants to continue taking these pills during the month of Ramadan so that she can interrupt menstruation and not have to break her fast since she will not menstruate as long as she takes them. Is this legally permissible? Please provide me with evidence.

Menses is a legal excuse for not fasting and praying

It is impermissible for menstruating women to fast or pray. If menstrual flow stops in a natural manner or by taking medicine, there is then no objection to fasting and praying.

The ruling
It is permissible to take pills to delay menses provided they are prescribed by a physician to avoid harm, following the legal axiom that states: "Do not cause harm and do not reciprocate harm."
Allah Almighty knows best.