They had yet another “garter” to put on. It went around the waist and had two straps hanging down front and back. They’d tie “menstrual cloths” on with them. At first it was just cloth. At some point, they even had disposable ones filled with natural fibers like very fine woodchips for women who could afford them. SO glad I didn’t live back then. Open underpants with menstrual cloths sounds like a nightmare waiting to happen.