Nurses during World War I notice that the absorbancy of bandages work much better for menstrual pads than other materials. They begin to use them, and attract the attention of Kotex, which markets a new product.
The marketing materials focus on menstruation as a "problem" to conceal. This is the first move toward disposability for menstrual products rather than rewashed cloth. The company recommends that customers "ask for them by name" (Kotex) at stops to avoid the "embarrassment" of requesting sanitary pads.