How it works: The dome-shaped cup is inserted into your vagina to cover the cervix. You should use spermicide to increase effectiveness.
Success rate: Of women who always use the diaphragm correctly, six out of 100 become pregnant. If it's not used correctly, 16 out of 100 will become pregnant.
Pros: It usually cannot be felt by a partner, can be inserted hours before sex, and has no impact on your hormones. It also falls under Obamacare's free birth control mandate.
Cons: It does not protect against STIs and requires a fitting by your doctor. It cannot be used during your period, can be difficult to insert, which you have to do each time you have sex, and may move around during sex.