Whosoever break the fast during Ramadan or didn't fast at all due to health concerns, is obliged to make up the missed fasts whenever she could so long as making up missed Ramadan didn't extend  to the coming one, and if next one arrived without fulling fasting the missed one, the ransom is 60 grams for each missed day (Equals 60 piasters to one Dinar for each day). And Allah The Almighty Knows Best.