It is Permissible to delay making up missed Ramadan Fasts until before the next Ramadan comes, and this is for those who broke the fast for a reason such as sickness, travel, menstruation and the like Sahih Muslim 1146 c
Translation
In another version of the previous hadith, the words are
" Yahya said: I think it was due to the regard for the Messenger of Allah (ﷺ)."