Barrier methods
A contraceptive cap or diaphragm is a circular dome made of thin, soft latex (rubber) or silicone. Caps are smaller than diaphragms, but they work in the same way.
They are inserted into the vagina before sex and cover the cervix to create a physical barrier to sperm entering the womb. They need to be used with a spermicide – spermicide contains a chemical that kills sperm.
If you do decide to use a cap or diaphragm for contraception, remember they offer almost no protection against sexually transmitted infections.