Breaking Saum becomes permissible only in case of a real need, emergency or danger. When a fast is broken on account of a valid reason qadha of the fast is obligatory. In such cases only qadha is necessary, not Kaffarah.
The following are valid reasons which make permissible the breaking of Saum:
(1) Sudden sickness which endangers one’s life, or which will cause great deterioration of health if the fast is not broken.
(2) When it becomes necessary to take medicine due to having been bitten by a poisonous animal.
(3) Extreme thirst, which endangers one’s life.
(4) A pregnant woman having genuine fear for either her own safety or the safety of the child she is bearing, may break the fast.
(5) A woman fearing for the life of the baby she is breast-feeding may break the fast. If her milk dries up as a result of the fast and the baby is dependant on breast-feeding, breaking the Saum is permissible.
(6) A Nafl fast may be broken to honour one’s guests. Qadha of the fast has to be made.