Sahih Muslim 2055
صحيح مسلم#2055SahihUmm Atiyya reported:We were commanded to go out as well as the hidden away ladies and those unmarried. She said menstruating women were to come out amongst you, but remain behind people and pronounce takbir (Allah-o-Akbar) along with them
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Every narration in Sahih Muslim is accepted as Sahih (authentic) by the established status of the book.
In-book reference: 8:11