Permissible Reasons for Breaking Fast in Ramadan

1- Sickness

It is permissible for the sick to break fast in Ramadan. Allah Almighty says:
�... but if any of you is ill or on a journey, the same number of days (should be made up) from other days�
(Al-Baqarah : 184).The sickness that permits the breaking of fast is the one that causes or leads to a more serious pain, if the sick were to fast.
2- Traveling

It is permissible for a traveler in the month of Ramadan to break his fast, and it is compulsory on him to pay back the missed days. Allah Almighty says:
�... but if any of you is ill or on a journey, the same number of days (should be made up) from other days.�
( Al-Baqarah : 184).The same distance that permits Al-Qasr (reduction of the number of prostrations in prayers) (Salat) also permits the breaking of fast, provided it is known as traveling according to the customs of the people and it is a permissible form of traveling. If, however, it is a form of sinful traveling or a traveling done in order to be free from fasting, then it will be prohibited for him to break his fast.However, if a traveler decides to fast, it will be valid. This is due to the hadeeth reported by Anas ibn Malik who said:
�We used to travel (during fasting) with the Prophet ﷺ, and those of us who fasted neither abused nor looked down upon those who broke their fast, nor did those who broke their fast look down upon those who fasted.�
[ Source: Bukhari.] However, this permission is upon the condition that fasting is not a burden on him nor a cause of pain for him. If it is, then it will be better for him not to fast. This is because the Prophet ﷺ in one of his journeys, saw a man whose fasting had become burdensome upon him (had been severely weakened) due to the severe heat, and as such people had gathered around him. Thereupon, the Prophet said:
�Fasting while on a journey is not part of righteousness.�
[ Source: Tirmidhi.]3- Pregnancy and Breastfeeding

A pregnant or breastfeeding woman who fears there would be a burden on herself if she fasted may break her fast, and she must pay it back, just like the sick.The Prophet ﷺ said:
�Allah Almighty has relieved the traveler of fasting and some parts of Salah (daily prayers), and He relieved the pregnant and the breastfeeding woman of fasting.�
[ Source: Bukhari.]However, if she fears the burden on only her child or fetus, then she must pay the missed fasts back and feed one poor person for every missed day. Ibn �Abbas said:
�As for the pregnant and breastfeeding women, if they fear the burden of fasting on their children, then they must pay it back (the missed fasts) and feed one poor person for every missed day.�
[ Source: Abu Dawud.]4- Menstrual and Post-Partum Bleeding

But a woman who menstruates or has post-natal bleeding is obligated to break her fast, as it is prohibited for her to fast. If, however, she does fast, it will not be valid; and she will still have to pay back the equivalent fasts for the period she missed. When �Aisha (may Allah be pleased with her) was asked why a menstruating woman pays back the missed fast, but not the missed prayers, she said:
�That (i.e. post natal and menstrual bleeding) used to befall us and we were ordered to pay back missed fasts, but not missed Salah (prayers).�
[ Agreed upon.]
source: islamkingdomfasting