Must a woman fulfill a vow she made to shave her newborn's head and donate money at the Al-Hussein Mosque in Cairo, and what are the consequences of not fulfilling it?

This vow is a vow of disobedience, and it is not permissible to fulfill it, because visiting graves for blessings and spending money on shrines and mausoleums is an innovation (bid'ah) and misguidance. The matter becomes even worse for this woman who vowed to shave the head of her newborn at the grave. If the shaving is an act of drawing closer to the occupant of the grave, it is major polytheism (shirk akbar). If it is for blessings, then it is a heinous innovation (bid'ah shani'ah) and a great misguidance. Scholars have unanimously agreed that if a woman knows that visiting a grave will lead to impermissible words or actions from her, then her visit is not permissible, without dispute. A vow to glorify a place or a grave or to draw closer to the one buried there is a null and void vow that is not binding, and it is impermissible to fulfill it by consensus. Shaving is no less significant than slaughtering and sacrificing. Therefore, this woman must repent to Allah with sincere repentance.