What is the supplication to be recited by women during menstruation, and is there a specific reward for repeating it 70 times at the time of each prayer, and what is the authenticity of the hadith mentioned concerning its virtue?

We do not know of the aforementioned supplication in the authentic Sunnah, and it is not permissible to attribute to the Messenger of Allah, peace and blessings be upon him, that which he did not say, "Whoever intentionally fabricates a lie against me, let him take his seat in the Hellfire." Not every narration is authentic; rather, verification is necessary. "It is sufficient a lie for a person to narrate everything he hears."

Secondly: It is permissible for a menstruating woman to remember Allah with whatever supplications and lawful remembrances she wishes. It is also permissible for her to recite the Quran without touching the Mushaf, either from memory or by using a barrier. There is no Sunnah that prohibits her from (reciting) the Quran, and the Hadith that prohibits it is weak by agreement of the people of knowledge.