In the following conditions, not to keep fasts is permitted, but one will have to keep them after Ramadaan month:
1. If one is on a journey, and if that journey is at least 92 Kilometers (57.5 miles) long.
2. Pregnant and breast-feeding women when she is concerned about the health of herself or the baby.
3. If a person is sick and he is concerned that the disease will get worst or will take longer time to cure or a healthy person, if he is sure to get sick.
4. Ladies having child birth and menstruation period. (Bahare Shari’at, part5)
5. A person is so old who is not capable of fasting nor he can hope of repeating the missed fasting then he should pay “Fidya” a fixed amount per day. That is to feed a poor twice for each fasting or give Sadaqa equivalent to Sadaqa Fitr. (Bahare Shari’at, part 5)