Is it permissible for a woman to travel for tourism and leave her infant with her mother?

If the mother can travel while ensuring her infant child is cared for, protected, and fed in a way that causes no harm, then there is no objection to her traveling. However, if the child would be harmed, then it is not permissible for her to travel, because the custody and care of the child are obligatory upon her if there is no one else. Custody is legally obligatory to protect the child from perishing and harm. It becomes an individual obligation (wajib ayni) if there is only one custodian available, and a communal obligation (wajib kifa'i) when there are multiple custodians. It is advisable for the mother to carefully consider her child's interests. If the travel is short and permissible, there is no objection. However, if it is long, such that she would be absent for days, then her primary duty is to care for her child.