Barrier methods are vaginal spermicides (foams, creams, suppositories), condoms, diaphragms, cervical caps and contraceptive sponges. Spermicides Vaginalschäume, creams and contain substances that form a chemical barrier to sperm by damaging the cell membranes of sperm, preventing fertilization. Most spermicides containing nonoxynol 9 and are available without prescription. These preparations is about the same effect; the pregnancy rate is 19% in ideal and 28% at typical (i. e. occasionally incorrect) application. The spermicide should be inserted into the vagina at least 10-30 minutes before sexual intercourse and again before each coitus. Because their efficiency is limited, spermicides are often used with other barrier methods. Against sexually transmitted diseases spermicides protect not reliable. Also spermicidal substances can cause vaginal irritation, which increases the risk of HIV transmission. Therefore, condoms are no longer moistened with nonoxynol 9th Condoms protect The use of condoms reduces the risk of sexually transmitted diseases, including for HIV infection. Condoms can be made of latex, polyurethane, silicone rubber and lamb intestine. Although condoms made from lamb intestines are impenetrable to sperm, but not for many viruses (eg., HIV), which can cause serious infections. Thus, condoms made of latex and polyurethane are preferred. They also protect against the human papilloma virus, reducing the risk for precancerous cervical lesions is reduced. The condom is the only reversible contraceptive method for men, except for the coitus interruptus, which is much less effective. The male condom is applied before penetration; The pinched together tip is placed, wherein it should project over the penis end by approximately 1 cm, to be able to absorb the ejaculate. The female condom is a tube having an inner and an outer ring; the inner ring is inserted into the vagina, the outer ring remains outside and covers the peritoneum. It should not be used more than 8 hours prior to intercourse and maintained for 6 hours after intercourse in the vagina. So that the ejaculate is collected in the Kodom, the penis is gently guided through the outer ring. When you remove the penis after sexual intercourse, make sure that the condom does not leak. Does the condom, it slips out or breaks it should be an emergency contraceptive to be applied. At each coitus a new condom is used. The pregnancy rate is the male condom in the first year, applied according to regulations at 2%, but about 18% lower than typical (ie inconsistent) application and the female condom at 5% below applied according to regulations and 21% under typical Application. Diaphragm The diaphragm is a dome-shaped rubber shell with a flexible rim which fits over the cervix and the upper portion and the lateral wall of the vagina. Diaphragms are available in different sizes. They are typically used with a spermicide and together form an effective barrier to sperm. The spermicide is applied to the Diaphrama before insertion. After the first coitus or sexual each further additional spermicide should be placed in the vagina. Diaphragms can be washed and reused. A health assistant (n. D. Übers .: in Germany a doctor) adjusts the diaphragm for a woman, so it is comfortable for her and her partner. After childbirth or significant weight change to the woman needs to be adjusted again. The diaphragm should remain for at least 6-8 hours, but not more than 24 hours after sexual intercourse in situ. In contrast, the pregnancy rates are at a correct application about 6% in the first year, in typical use about 12%. Diaphragms were once widely used (one third of women in 1940), in 2002 only 0.2% of US women said they use them. This decrease in the application is mainly due to the development of many other, more effective methods of contraception. Another reason may be that for adjusting a doctor must be consulted and that adverse effects (eg. As pain, vaginal irritation) may occur. Currently, a new diaphragm is developed. Of the diaphragm is believed that one size fits most women. It is made of silicone and is said to be softer and more durable than traditional latex diaphragms. The application of this diaphragm may be useful in developing countries with limited medical care. The Zervixkappe Zervixkappe is similar to the diaphragm in the form of, but smaller and more rigid. It must be inserted before intercourse and should be left for at least 6 hours after intercourse and no longer than 48 hours in situ. The pregnancy rates in typical use rate is 8% in the first year; in women who have given birth, the pregnancy rates are heights, because after birth, a secure hold is difficult. In the US, only one Zervixkappe is available. They are (small, medium, large) in 3 sizes, wherein the size is selected in dependence of a previous pregnancy. a health assistant has before use a Zervixkappe (translator’s note .: a doctor in Germany..) a prescription; individual adjustment is not required. Contraceptive sponge The contraceptive sponge acts both as Bariere as a spermicidal substance. It can be purchased without a prescription and is up to 24 hours before intercourse introduced. The sponge should remain for at least 6 hours after intercourse in situ. The maximum wearing time should not be longer than 30 hours. The pregnancy rates in typical use in women who have never been born, be 12% and in women who have given birth, 24%.