The permissibility of carrying children during prayer, and their garments are regarded as being pure until it is realized that they are impure. Few actions will not invalidate the prayer, and the same applies if several such actions are done but are done separately
حَدَّثَنِي أَبُو الطَّاهِرِ، أَخْبَرَنَا ابْنُ وَهْبٍ، عَنْ مَخْرَمَةَ بْنِ بُكَيْرٍ، ح قَالَ وَحَدَّثَنَا هَارُونُ بْنُ سَعِيدٍ الأَيْلِيُّ، حَدَّثَنَا ابْنُ وَهْبٍ، أَخْبَرَنِي مَخْرَمَةُ، عَنْ أَبِيهِ، عَنْ عَمْرِو بْنِ سُلَيْمٍ الزُّرَقِيِّ، قَالَ سَمِعْتُ أَبَا قَتَادَةَ الأَنْصَارِيَّ، يَقُولُ رَأَيْتُ رَسُولَ اللَّهِ صلى الله عليه وسلم يُصَلِّي لِلنَّاسِ وَأُمَامَةُ بِنْتُ أَبِي الْعَاصِ عَلَى عُنُقِهِ فَإِذَا سَجَدَ وَضَعَهَا .
Abu Qatada reported: I saw the Messenger of Allah (ﷺ) leading the people in prayer with Umama daughter of Abu'l-'As on his neck; and when he prostrated he put her down.