'Menstrual' in the Bible

‘Also you shall not approach a woman to uncover her nakedness during her menstrual impurity and ceremonial uncleanness.

If a man lies [intimately] with a woman during her menstrual cycle and uncovers her nakedness, he has exposed her flow, and she has uncovered the flow of her blood; both of them shall be cut off from their people [excluding them from the atonement made for them].