A menstrual cycle should be 26-32 days. It means bleeding to bleeding gape should be 26-32 days. First day of the bleeding is the first day of the cycle. If you have a cycle of 28 days then you can predict your next due date. By doing this you can not have any idea about miscarriage. Some ladies can get miscarriage with normal cycle interval and they even don't know that they were pregnant.
