Q: Is it permissible to take tablets to delay the periods / menstruation, so that the full 30 days fast can be kept?
A. This will be permissible but detrimental to your health. Do not interfere in the system created by Allah Ta’aala for our bodies. The Qadhaa of the missed fasts which will be kept after Ramadhaan will bring the same reward, so why endanger your health? This method of taking medication to stop the periods is unnecessary.