Internal condoms — also called “female condoms” — and diaphragms are both birth control methods, but they have key differences. Internal condoms are larger and about the same length as regular condoms. They can be used in the vagina, but can also be used in the anus to protect against STDs. When put in the vagina, internal condoms help protect you from pregnancy and STDs when used correctly.
Diaphragms are small, shallow, cup-shaped disks that cover the bottom of your cervix to stop sperm from joining an egg. They’re 88% effective at preventing pregnancy when used with spermicide as directed. Diaphrams don’t protect you against STDs, so use a condom with a diaphragm every time you have sex.