[Using medication to prevent menstruation in Ramaḍān and during Ḥajj]

Answer: That is permissible; her fasting is valid, and likewise her circumambulations; she is judged to be pure. This is understood from the evidences in this chapter, such as His saying, Exalted is He: “And they ask you about menstruation. Say, ‘It is harm, so keep away from wives during menstruation and do not approach them until they are pure …’” [al-Baqarah:222].
In this verse, menstruation is the harm that issues from the womb; if no such harm issues from the womb, the woman is pure.
Source : Min Thimār al-ʿIlm wa al-Ḥikmah vol.1