Barrier contraception methods work by physically stopping the sperm from fertilising the egg. Some barrier methods (e.g. condoms) also provide protection against some sexually transmitted infections (STIs) including chlamydia and HIV, and stop them being passed from one sexual partner to another.
Condoms act as a barrier to prevent sperm from entering the vagina.
Male condoms cover the whole of the penis and are available in lots of different shapes, sizes, colours and flavours (for use in oral sex). If used correctly condoms are 98% effective in preventing unintended pregnancies but they sometime split or come off during sex – usually through incorrect use. This brings the typical use effectiveness rate down to 83%.
The female condom (sometimes called a Femidom) has an internal ring that is placed inside the vagina. The condom then lines the vagina and the opening lies just outside. If used correctly female condoms are 95% effective in preventing unintended pregnancies but they sometime come out during sex – usually through incorrect use – or a man may inadvertently puts his penis between the condom and the vaginal wall. This brings the typical use effectiveness rate down to 79%.
You can find out more about the female condom from the NHS Choices website here
Diaphragms and Caps
Diaphragms and caps are considered to be less effective as methods of contraception but may be the contraception method of choice for some women as they do not involve taking hormonal contraception.
Diaphragms and caps come in a variety of different shapes and sizes and are basically a latex or rubber device that holds spermicidal jelly, gel or cream. They fit just inside the vagina over the cervix (the opening to the womb). Diaphragms and caps can be put in place any time before sex but need to be left in place for at least 6 hours after sex before removing.
Diaphragms and caps do have a higher failure rate than the more effective long acting methods and are at best only 83% effective in typical use.
You can find more information on the NHS Choices website about diaphragms here and caps here.