Unless there exists a particular circumstance that genuinely necessitates it, it is not considered appropriate to use medication for the purpose of delaying menstruation. Menstruation is a divinely ordained natural law; refraining from fasting during this state is likewise a ruling established by Allah. When one may simply submit to the natural disposition (fiṭrah) created by Allah and to the ruling He has prescribed, attempting to alter that natural state out of dissatisfaction would amount to stepping beyond the proper bounds of obedience.
Indeed, just as fasting is a command of the Most High, so too is it His command that women do not fast during their menstrual period. Thus, in either condition, a woman is in compliance with the divine command. Moreover, this matter does not constitute a situation of necessity—such as may arise in the context of ḥajj or ʿumrah—for missed fasts can be made up at any point throughout the year.