Answer: There is no objection so long as those pills do not harm her health and they indeed stop the menstrual flow. She may take them, and as long as no blood appears her fast remains valid.
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Those Permitted to Break the Fast in Ramadan
Question: Who are the people allowed to break the fast in Ramadan?
Answer: Permission to break the fast in Ramadan is granted to those who have legitimate excuses recognized by the Sacred Law.

1. The traveller whose journey is long enough to allow the shortening of the prayers.
2. The sick person who would endure hardship if he fasted, or whose illness would worsen, or whose recovery would be delayed; such a person may break the fast.
3. A woman who is menstruating and a woman experiencing post-partum bleeding (nifās). It is impermissible—and indeed forbidden—for them to fast during these states, because they fall under valid excuses.
4. The pregnant woman and the nursing mother: if either fears for her own well-being or for her child, she is permitted to break the fast.
5. The chronically ill person for whom no cure is expected, and the very elderly. All of these fall under the category of people with excuses for whom the Lawgiver has allowed the breaking of the fast.

Among them are those who must later make up the missed days: the traveller, the sick person expected to recover, the menstruating woman, the woman in post-partum bleeding, and the pregnant and nursing women. All of these are required to make up an equal number of other days, as Allah the Exalted says: “then a number of other days” (al-Baqarah 2:184).