You are discussing the commandment of Tarahas HaMischpacha, or “family purity.” This regards the state of Niddah, or “ritual impurity,” of a woman during her times of bleeding. It doesn’t mean she is “bad.” But it means that she must avoid contact with sacred things and that her husband must avoid sexual contact with her. The two most obvious times are during her menstrual cycle and after childbirth. When her time of Niddah is ended, she goes to the Mikveh, the ritual bath where there is a natural flow of water, and immerses. All observant Jewish women do this, they always have, they always will, regardless of how rich or poor they are – it is a commandment.
Of course this is what Luke 2:22 is referring to. Kudos to you for spotting this.