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

وَحَدَّثَنَا مُحَمَّدُ بْنُ الْمُثَنَّى، حَدَّثَنَا عَبْدُ الْوَهَّابِ، ح وَحَدَّثَنَا عَمْرٌو النَّاقِدُ، حَدَّثَنَا سُفْيَانُ، كِلاَهُمَا عَنْ يَحْيَى، بِهَذَا الإِسْنَادِ وَلَمْ يَذْكُرَا فِي الْحَدِيثِ الشُّغْلُ بِرَسُولِ اللَّهِ صلى الله عليه وسلم ‏.‏