Early 20th century intracervical and intrauterine pessaries.
I think the point of early 20th century birth control was to make it too painful to have sex.
And believe it or not, these devices were considered a significant improvement when they came out in the 1890s.
I realize that people might want to know about just what these things are. Here is the link to the article where I got the picture. Anyone on a university account should be able to access it for free. It's a great article on the history of birth control that I recommend for anyone. It's at least worth a look for the pictures. And if this link doesn't work, it is from the September 2000 issue of the Journal of American History.