I saw my grandma yesterday (B. 1929) and I asked her about periods back then. This is what she said (paraphrased):
Me: So what happened when you first got your period? GM: I was 12 and I had no idea what it was! My mother saw the blood in my panties and handed me a pad and a belt. It was then that she told me about periods.
Me: What about tampons? GM: I never even heard of them until the 50s. They weren't really widely used until then.
Me: Were pads "hidden" behind the counter or were they out in the open like today? GM: They were out on the shelves just like today, but I used to be so embarassed to buy them! I would get my mom to do it (she says while laughing!)
And to make this post even more of a spectacle, here are some period ads from the 30s to the 60s and some douche ads thrown in for fun.
1932: Need help talking to your 12 year old daughter?
1937: If "men were men" in the "Golden Era" I surly hope these ads are full of shit…