Reference: Fataawa Ramadhaan v2 p592 no.578
al-Muntaqaa v1 p34
Question: The questioner says she had an operation on her throat and the doctor advised her not to fast the month of Ramadhaan. So is she required to make an expiation or [just] make up [the missed fasts]?
Response: She is required to make up the days she did not fast, as Allaah سبحانه و تعالى says:
{…and whoever is ill or on a journey, the same number [of days which one did not observe fasts must be made up] from other days} al-Baqarah 2:185
And it was because of this illness (operation) that she had not fasted, so she must make up the [fast for the] days she had not fasted.
