If one amongst us had to break fasts (of Ramadan due to natural reasons, i. e. menses) during the life of the Messenger of Allah ﷺ she could not find it possible to complete them so long she had been in the presence of Messenger of Allah ﷺ till Sha'ban commenced. (Using translation from Muslim 1146e)  

أَنَّهَا قَالَتْ «إِنْ كَانَتْ إِحْدَانَا لَتُفْطِرُ فِي زَمَانِ رَسُولِ اللَّهِ ﷺ فَلَمْ تَقْدِرْ أَنْ تَقْضِيَهُ مَعَ النَّبِيِّ ﷺ حَتَّى يَأْتِيَ شَعْبَانُ مَا كَانَ النَّبِيُّ ﷺ يَصُومُ فِي شَهْرٍ مَا كَانَ يَصُومُهُ فِي شَعْبَانَ كَانَ يَصُومُهُ إِلَّا قَلِيلًا بَلْ كَانَ يَصُومُهُ كُلَّهُ»  

[Machine] "I and Hafsah became voluntary fasters, so food was presented to us and we broke our fast. Then the Messenger of Allah ﷺ said, 'Observe the fast again on another day in place of this one.'"  

أَصْبَحْتُ أَنَا وَحَفْصَةُ صَائِمَتَيْنِ مُتَطَوِّعَتَيْنِ فَأُهْدِيَ لَنَا طَعَامٌ فَأَفْطَرْنَا فَقَالَ رَسُولُ اللَّهِ ﷺ «صُومَا مَكَانَهُ يَوْمًا آخَرَ»  

[Machine] The Messenger of Allah ﷺ said: "Whoever vomits involuntarily while fasting, there is no need for them to make up for the fast. But whoever deliberately induces vomiting, they must make up for the fast."  

قَالَ رَسُولُ اللَّهِ ﷺ «مَنْ ذَرَعَهُ الْقَيْءُ وَهُوَ صَائِمٌ فَلَيْسَ عَلَيْهِ قَضَاءٌ وَمَنِ اسْتَقَاءَ فَلْيَقْضِ»  

[Machine] On the authority of the Messenger of Allah ﷺ , he said, "If a fasting person eats or drinks forgetfully, then let him complete his fast, for indeed Allah has provided him with food and drink."  

عَنْ رَسُولِ اللَّهِ ﷺ قَالَ «إِذَا أَكَلَ الصَّائِمُ نَاسِيًا وَشَرِبَ نَاسِيًا فَلْيُتِمَّ صَوْمَهُ فَإِنَّمَا أَطْعَمَهُ اللَّهُ وَسَقَاهُ»  

"Whoever eats out of forgetfulness while fasting, let him complete his fast, for it is Allah Who has fed him and given him to drink." (Using translation from Ibn Mājah 1673)   

قَالَ رَسُولُ اللَّهِ ﷺ «إِذَا أَكَلَ الصَّائِمُ نَاسِيًا فَلْيُتِمَّ صَوْمَهُ فَإِنَّمَا أَطْعَمَهُ اللَّهُ وَسَقَاهُ»  

[Machine] The Prophet ﷺ said, "Whoever breaks their fast in the month of Ramadan forgetfully, there is no make-up (obligatory fasting) or expiation (atonement) upon them."  

أَنَّ النَّبِيَّ ﷺ قَالَ «مَنْ أَفْطَرَ فِي شَهْرِ رَمَضَانَ نَاسِيًا فَلَا قَضَاءَ عَلَيْهِ وَلَا كَفَّارَةَ»  

[Machine] A man asked the Messenger of Allah ﷺ and said, "O Messenger of Allah, I was fasting and ate and drank by mistake." The Messenger of Allah ﷺ said, "Allah has fed you and given you drink. Complete your fast."  

أَنَّ رَجُلًا سَأَلَ رَسُولَ اللَّهِ ﷺ فَقَالَ يَا رَسُولَ اللَّهِ إِنِّي كُنْتُ صَائِمًا فَأَكَلْتُ وَشَرِبْتُ نَاسِيًا فَقَالَ رَسُولُ اللَّهِ ﷺ «أَطْعَمَكَ اللَّهُ وَسَقَاكَ أَتِمَّ صَوْمَكَ»