If anyone stopping her menstruation cycle by using medicine in Ramadan month by using this system then sawm is lawful or unlawful for her?

Answered according to Hanafi Fiqh by Darulifta-Deoband.org

بسم الله الرحمن الرحيم

(Fatwa: 638/603/SN=09/1436)

In case a woman does not experience menstruation on time in the month of Ramadan as a result of consuming medicine then it is fardh on her to offer salah and keep fast. But this initiative (stopping a natural process with medicine) is very dangerous for health, hence she should avoid it.

Allah knows Best!

Darul Ifta,
Darul Uloom Deoband