Does a mother's prayer become nullified if her daughter's bare bottom touches her foot during the prayer?

The touching of a child's bottom to her mother's foot while she is praying does not invalidate the prayer, unless the child's bottom carries a wet or dry impurity (najāsa) and this impurity transfers to the mother's foot and is not removed immediately. In that case, the prayer becomes invalid due to the condition of purification from impurities. However, if there is no impurity, the prayer is not invalidated.