All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger. We ask Allaah to exalt his mention as well as that of his family and all his companions.
Getting the reward of the Night of Decree is not restricted to performing the prayer, the thing which a woman in menses can not do. She may do other things that are within her reach, like reciting the Quran from memory - according to the most preponderant opinion of the scholars - praising Allaah, seeking Allaah's forgiveness, giving charity, and performing other good deeds that do not require a person to be in a state of purity. However, if you take pills in order to delay your menses so that you take advantage of the Night of Decree and be in total purity, then you may do so and you will be rewarded, in all cases, Allaah willing, provided that those pills do not cause you any harm. Nonetheless, in our view, it is preferable that you be pleased with the menses that Allaah had decreed for you, and stick to Allaah's Order by not performing the prayer during the days of your menses.
Allaah Knows best.