Is it permissible to perform Hajj with an infant, and is there any harm in it for them?

It is permissible to travel with a child for Hajj, unless a definite harm results from it. The validity of a child's Hajj is confirmed by their guardian's entering into ihram on their behalf.

As for the occurrence of harm to an infant due to Hajj, this matter should be referred to specialists. If definite harm to the infant is proven and the mother finds no one to care for them, this is considered a valid excuse permitting her to forgo the obligatory Hajj.