The holy month of Ramadan requires Muslims abstain from eating and drinking from sunrise to sunset each day. For the most part, that is considered an unbreakable rule. However, there are some instances in which one may take leave of the fast. According to the holy Koran, people who are sick, elderly, traveling, pregnant or breast-feeding, as well as children under the age of puberty, can forgo fasting if it will negatively affect their health. Additionally, a fast can become invalidated for reasons such as menstruation or postpartum bleeding, intentional vomiting and, of course, breaking a fast to eat or drink. In all these cases, the Koran requires that believers take a qada fast — meaning to fast one day for one day — to make up for the missed days of fasting, as soon as possible.