Here's something I'll bet you didn't know (which is another way of saying, “I just learned this myself”): Sanitary napkins (more specifically the first such – Kotex) are a by-product of World War I.
The story goes as follows: Because Egypt grew most of the world's cotton at the time and Egypt was cut off from Europe and North America by the war, there was a shortage of cotton. There was also a great need for bandages, which were, of course, made from cotton.
Kimberley-Clark came to the rescue with a product it called cellucotton, made from wood fiber (which, amazingly, they patriotically sold to the US government at cost). Red Cross nurses at the front didn't take long to figure out another use for cellucotton, which was highly absorbent.
After the war, Kimberley-Clark introduced Kotex. The product took a while to catch on, though, since magazines refused to accept ads for it.