Allah says that whoever is sick or on a journey fasts the same number of other days, and for those who can fast only with great difficulty there is a fidyah of feeding a poor person (2:184). Allah intends ease for you and not hardship (2:185). Aisha said that menstruating women were commanded to make up the fasts and not the prayers.
1Who may break the fast
The sick, whose illness would be worsened by fasting.
The traveller, for the length of the journey (the distance is as for shortening the prayer).
A woman in her period or postnatal bleeding must break it.
A pregnant or nursing woman who fears for herself or her child.
The very old, and those with a chronic illness with no hope of recovery.
2What they owe
The sick and the traveller: make up the days later.
The woman in her period: make up the days later.
The very old and the chronically ill: feed one poor person for every missed day (fidyah).
A pregnant or nursing woman: the majority make up the days. Some add the fidyah when she feared for her child only.
3Making up
The days can be made up at any time before the next Ramadan, one after another or separately.
If a person delays it with no excuse until the next Ramadan, he fasts and also pays the fidyah according to most schools (the Hanafi school says there is only the making up).
Where the schools differ
The four Sunni schools agree on the main ruling above and differ in these points. No school is preferred here.
Travel. the traveller is better fasting if it is not hard, and breaking it if it is, according to most scholars. The Zahiris say breaking it in travel is obligatory.
Días contados. Y quien de vosotros esté enfermo o de viaje, un número igual de días. Y los que, pudiendo, no ayunen podrán redimirse dando de comer a un pobre. Y, si uno hace el bien espontáneamente, tanto mejor para él. Pero os conviene más ayunar. Si supierais...
Es el mes de ramadán, en que fue revelado el Corán como dirección para los hombres y como pruebas claras de la Dirección y del Criterio. Y quien de vosotros esté presente ese mes, que ayune en él. Y quien esté enfermo o de viaje, un número igual de días. Alá quiere hacéroslo fácil y no difícil. ¡Completad el número señalado de días y ensalzad a Alá por haberos dirigido! Quizás, así seáis agradecidos.
From the Sunnah
Sahih Muslim 335aAuthentic collection
The point of the hadith: Aisha said that the women were commanded to make up the fasts and were not commanded to make up the prayers.
This is general information, not a fatwa. For your own situation, ask a qualified scholar.
Fiqh questions
Excuses for not fasting and how to make up the days
Allah says that whoever is sick or on a journey fasts the same number of other days, and for those who can fast only with great difficulty there is a fidyah of feeding a poor person (2:184). Allah intends ease for you and not hardship (2:185). Aisha said that menstruating women were commanded to make up the fasts and not the prayers.
Is this a fatwa?
No. It is a summary of well-known rulings with their evidence. For your own case, ask a qualified scholar.
What if my school differs from this answer?
Follow the view of the school you follow and the scholar who teaches you. The page lists the differences of the four schools.