It was narrated from Anas bin Malik that:

he came to Prophet in Al-Madinah when he was eating breakfast. The Prophet ﷺ said to him: "Come and eat the breakfast." He said: "I am fasting." The Prophet ﷺ said to him: "Allah, the mighty and sublime, has waived fasting and half of the prayer for the traveler and for pregnant and breastfeeding women."

أَخْبَرَنَا عَمْرُو بْنُ مَنْصُورٍ، قَالَ حَدَّثَنَا مُسْلِمُ بْنُ إِبْرَاهِيمَ، عَنْ وُهَيْبِ بْنِ خَالِدٍ، قَالَ حَدَّثَنَا عَبْدُ اللَّهِ بْنُ سَوَادَةَ الْقُشَيْرِيُّ، عَنْ أَبِيهِ، عَنْ أَنَسِ بْنِ مَالِكٍ، رَجُلٌ مِنْهُمْ أَنَّهُ أَتَى النَّبِيَّ ﷺ بِالْمَدِينَةِ وَهُوَ يَتَغَدَّى فَقَالَ لَهُ النَّبِيُّ ﷺ " هَلُمَّ إِلَى الْغَدَاءِ " . فَقَالَ إِنِّي صَائِمٌ . فَقَالَ لَهُ النَّبِيُّ ﷺ " إِنَّ اللَّهَ عَزَّ وَجَلَّ وَضَعَ لِلْمُسَافِرِ الصَّوْمَ وَشَطْرَ الصَّلاَةِ وَعَنِ الْحُبْلَى وَالْمُرْضِعِ " .