Does Period Break Fast?
The temporary impurity which can be removed is one thing and the start of the impure period, which cannot be shaken off until it completes is another. It is important to worship when one is pure or can attain purity. To keep fast along with the state of impurity does not go with the spirit of worship. The concession was given to the temporary impurity of ehtalam, but not to the impurity of the menstrual cycle.