This is a small, soft, silicone dome that is inserted into the vagina and sits over the cervix.  

By acting as a barrier, it prevents sperm passing through the cervix and into the womb.

You must use the method with a spermicide, so in addition works to kill sperm.  

When used correctly and consistently, diaphragms and caps are estimated to be between 92-96% effective.

They must stay in place for six hours after sex.  

Diaphragms are designed to be able to fit most women, however you may not be suitable for this method if you have an unusually shaped or positioned cervix, your vaginal muscles are unable to hold it in place, you are prone to recurrent urinary tract infections (UTIs), you have ever had toxic shock syndrome or have a sensitivity to the materials and spermicide used.  

At any time before sex, if it has been in place for three or more hours, then more spermicide will need to be applied before sexual activity.  

The diaphragm only needs to be used when having sexual contact, there are usually no serious associated side effects or risks to health.

It will not protect against STIs and is not as reliable as other methods of contraception.

The diaphragm relies on you remembering to use correctly which can take some getting used to.

The diaphragm can cause UTIs, and some people may be sensitive to the materials or spermicide.