Before inserting or removing a<unk>  one's hands should be washed to avoid introducing harmful bacteria into the vaginal canal. The rim of a<unk> is squeezed into an oval or arc shape for insertion. A water-based lubricant (usually spermicide) may be applied to the rim of the<unk> to aid insertion. One teaspoon (5 mL) of spermicide may be placed in the dome of the<unk> before insertion, or with an applicator after insertion. The<unk> must be inserted sometime before sexual intercourse, and remain in the vagina for 6 to 8 hours after a man's last ejaculation. For multiple acts of intercourse, it is recommended that an additional 5 mL of spermicide be inserted into the vagina (not into the dome—the seal of the<unk> should not be broken) before each act. Upon removal, a<unk> should be cleansed with mild soap and warm water before storage. The<unk> must be removed for cleaning at least once every 24 hours and can be re-inserted immediately. Oil-based products should not be used with latex<unk> . Lubricants or vaginal medications that contain oil will cause the latex to rapidly degrade and greatly increases the chances of the<unk> breaking or tearing. Natural latex rubber will degrade over time. Depending on usage and storage conditions, a latex<unk> should be replaced every one to three years. Silicone<unk>  may last much longer—up to ten years. Effectiveness The effectiveness of<unk> , as of most forms of contraception, can be assessed two ways: method effectiveness and actual effectiveness. The method effectiveness is the proportion of couples correctly and consistently using the method who do not become pregnant. Actual effectiveness is the proportion of couples who intended that method as their sole form of birth control and do not become pregnant; it includes couples who sometimes use the method incorrectly, or sometimes not at all. Rates are generally presented for the first year of use. Most commonly the Pearl Index is used to calculate effectiveness rates, but some studies use decrement tables. For all forms of contraception, actual effectiveness is lower than method effectiveness, due to several factors: * mistakes on the part of those providing instructions on how to use the method * mistakes on the part of the method's users * conscious user non-compliance with method For instance, someone using a<unk> might be fitted incorrectly by a health care provider, or by mistake remove the<unk> too soon after intercourse, or simply choose to have intercourse without placing the<unk>  Contraceptive Technology reports that the method failure rate of the<unk> with spermicide is 6% per year. The actual pregnancy rates among<unk> users vary depending on the population being studied, with yearly rates of 10% to 39% being reported. Unlike some other cervical barriers, the effectiveness of the<unk> is the same for women who have given birth as for those who have not. Advantages The<unk> does not interfere with a woman's menstrual cycle, therefore, no reversal or wait time is necessary if contraception is no longer wanted or needed. The<unk> only has to be used during intercourse. Many women, especially those who have sex less frequently, prefer barrier contraception such as the<unk> over methods that require some action every day. Like all cervical barriers,<unk>  may be inserted several hours before use, allowing uninterrupted foreplay and intercourse. Most couples find that neither partner can feel the<unk> during intercourse. The<unk> is less expensive than many other methods of contraception. Sexually transmitted infections There is some evidence that the cells in the cervix are particularly susceptible to certain sexually transmitted infections (STIs). Cervical barriers such as<unk>  may offer some protection against these infections. However, research conducted to test whether the<unk> offers protection from HIV found that women provided with both male condoms and a<unk> experienced the same rate of HIV infection as women provided with male condoms alone. Because pelvic inflammatory disease (PID) is caused by certain STIs,<unk>  may lower the risk of PID. Cervical barriers may also protect against human papillomavirus (HPV), the virus that causes cervical cancer, although the protection appears to be due to the spermicide used with<unk>  and not the barrier itself.<unk>  are also considered a good candidate as a delivery method for microbicides (preparations that, used vaginally, protect against STIs) that are currently in development.
Diaphragm 
Epigastrium
Thoracic diaphragm
Airtraq
Gumma 
Ainhum
Azasteroid
Hippus