What is the ruling on carrying an infant during prayer whose diaper contains impurity, without the worshiper's knowledge of it?

If someone prays while knowing there is impurity on their clothes, body, or prayer mat, their prayer is invalid. However, if they are unaware of the impurity, their prayer is valid, and they are not required to repeat it. This is supported by what Abu Dawud narrated from Abu Sa'id al-Khudri (may Allah be pleased with him) that the Prophet (peace be upon him) removed his sandals during prayer and, after finishing, informed them that Jibril had told him there was filth on them. The Prophet's (peace be upon him) continuation of his prayer indicates the validity of the prayer of one who prays while unaware of an impurity on them. Therefore, if someone carries a child whose diaper contains impurity while knowing about it, their prayer is invalid. But if they are unaware, their prayer is valid.