The<unk> is a barrier method of birth control. It is moderately effective, with a one-year failure rate of around 12% with typical use. It is placed over the cervix with spermicide before sex and left in place for at least six hours after sex. Fitting by a healthcare provider is generally required. Side effects are usually very few. Use may increase the risk of bacterial vaginosis and urinary tract infections. If left in the vagina for more than 24 hours toxic shock syndrome may occur. While use may decrease the risk of sexually transmitted infections, it is not very effective at doing so. There are a number of types of<unk>  with different rim and spring designs. They may be made from latex, silicone, or natural rubber. They work by blocking access to and holding spermicide near the cervix. The<unk> came into use around 1882. It is on the World Health Organization's List of Essential Medicines.
Diaphragm 
Epigastrium
Thoracic diaphragm
Airtraq
Gumma 
Ainhum
Azasteroid
Hippus