Monday, February 11, 2008

Spermicidal and Barrier Contraception

Barrier contraceptives are devices that provide a physical barrier between the sperm and the egg. Examples of barrier contraceptives include the male condom, female condom, diaphragm, cervical cap, and sponge. [For a description of the male condom, see Box Male Condom.] Barrier devices are the only contraceptive methods that can help prevent sexually transmitted diseases (STDs).

Spermicides
Spermicides are sperm-killing substances available as foams, creams, or gels, and are often used in female contraception with barrier and other devices. Spermicides are usually available without a prescription or medical examination.

The active ingredient in U.S.-made spermicides is usually nonoxynol-9, which attacks the surface of the sperm cell. Nonoxynol-9, however, does not provide any additional protection against sexually-transmitted diseases. In fact, research indicates that frequent use can cause vaginal irritation and abrasions and actually increase the risk for HIV transmission in women. In addition, use of a spermicide with a barrier device doubles or triples the risk for a urinary tract infection in women, regardless of whether the device is a condom or diaphragm. Spermicides are no longer recommended with male condoms. (Non-spermicidial lubricated condoms are safe to use.) Some experts think they are not necessary for use with diaphragms, but this issue is still under debate.

In general, spermicides may be an appropriate choice for women who have intercourse only once in a while, or need backup protection against pregnancy (for instance, if they forget to take their birth control pills). Spermicides should not be used alone as the primary method of birth control. Nor should they be used to prevent sexually transmitted diseases.

Diaphragm
The diaphragm, which is generally used with a spermicidal cream, foam, or gel, is a small dome-shaped latex cup with a flexible ring that fits over the cervix. The cup acts as a physical barrier against the entry of sperm into the uterus. The spermicide provides added chemical protection but, as stated above, some experts think they are not necessary for use with diaphragms.

The diaphragm is a flexible rubber cup that is filled with spermicide and self-inserted over the cervix prior to intercourse. The device is left in place several hours after intercourse. The diaphragm is a prescribed device fitted by a health care professional and is more expensive than other barrier methods, such as condoms.
There are three basic rim designs:

The Arcing Spring diaphragm applies strong pressure and easily flips into place. It is useful for women with weak vaginal muscles and for new users who are worried about incorrect placement.

The Coil Spring Rim is useful for women with strong vaginal muscles.
The Flat Spring Rim has a delicate rim and a gentle spring, and may be appropriate for women who have not had children.

Diaphragms come in different sizes and require a fitting by a trained health care provider. The health care provider also advises and prescribes the correct size of diaphragm for the user. Some women will need to be refitted with a different-sized diaphragm after pregnancy, abdominal or pelvic surgery, or weight loss or gain of 10 pounds or more. As a general rule, diaphragms should be replaced every 1 - 2 years.

Although the diaphragm has a relatively high failure rate, even with perfect use, it is considered a good choice for women whose health or lifestyle prevents them from using more effective hormonal contraceptives. Certain conditions of the vagina and uterus, a history of toxic shock syndrome, or a history of recurrent urinary tract infections, may disqualify a woman from using the device. The diaphragm should not be used if either partner is allergic to latex or spermicides.

Using and Inserting the Diaphragm. The diaphragm can be placed in the vagina up to 1 hour before intercourse and can be used even when a woman is menstruating. The following are general guidelines for insertion:

Before or after each use, the woman should hold the diaphragm up to the light and fill it with water to check for holes, tears, or leaks.
A small amount of spermicide (about 1 tablespoon) is usually placed inside the cup, and some is smeared around the lip of the cup.

The device is then folded in half and inserted into the vagina by hand or with the assistance of a plastic inserter.

The diaphragm should fit over the cervix, blocking entry to the womb.
If more than 6 hours pass before repeat intercourse occurs, the diaphragm is left in place and extra spermicide is inserted into the vagina using an applicator.
The diaphragm must remain in the vagina for 6 - 8 hours after the final act of intercourse, and can safely stay there up to 24 hours after insertion.

The diaphragm should be washed with soap and warm water after each use and then dried and stored in its original container, which should be kept in a cool dry place.
Advantages of the Diaphragm. The diaphragm can be carried in a purse, can be inserted up to an hour before intercourse begins, and usually cannot be felt by either partner. It may protect against cervical gonorrhea, Chlamydia, and trichomoniasis, although more research is needed to confirm this. It does not provide protection against sexually-transmitted infections in areas other than the cervix.

Disadvantages and Complications of the Diaphragm. Some disadvantages or complications are as follows:

Failure rates are high, about 20% with typical use.
Some women dislike having to insert the device every time intercourse occurs or have trouble mastering the insertion and removal process.

Frequent urinary tract infections are a problem for some women. This difficulty can sometimes be resolved by a refitting, by urinating before inserting the device, or by urinating after intercourse.

Cases of toxic shock syndrome have been reported among diaphragm users, but it is very rare. To be safe, the diaphragm should not stay in place for more than 24 hours. (It is still important for pregnancy protection, however, to retain the diaphragm for 6 - 8 hours after intercourse.)

It provides protection against sexually transmitted disease only in the cervix, and women should not rely on it for protection against HIV.
Cervical Cap
The cervical cap (Prentif, FemCap) is a thimble-shaped latex cup that fits over the cervix. It is always used with a spermicidal cream or gel. It is similar to a diaphragm, but smaller, and is available in only four sizes. The cap is sold by prescription and requires a pelvic examination, Pap test, and fitting by a health care provider.

Insertion and Use of the Cervical Cap. After a small amount of spermicide is placed in the cap, the device is inserted by hand. As in diaphragm use, instruction and practice is required. The cap must be kept in the vagina for 8 hours after the final act of intercourse. Caps wear out and should be replaced every 1 - 2 years. A refitting may also be needed when a woman experiences certain changes in her health or physical status.

Candidacy for the Cervical Cap. Because of the restricted range of available sizes, about 1 in 5 woman will not be able to be fitted for the cap. The cap is not widely used, and some women, particularly those who live in sparsely populated areas, may not have access to health care professionals who are trained in fitting this device. Other conditions that can preclude cap use include:

An abnormal Pap test
A history of toxic shock syndrome
A sexually transmitted or reproductive tract infection
Inflammation of the cervix

The cap has little value for women who have had children, because the stretching of the vagina and cervix makes a proper fit more difficult and failure rates are high.
Advantages of the Cervical Cap. Among women who have never given birth, the cap's failure rate, at least with Prentif cervical cap, is similar to that of the diaphragm. (The FemCap appears to have a higher failure rate.) The cap in general is also similar to the diaphragm in terms of cost, ease of use, protection against STDs, and also the potential for latex or spermicidal allergies. But unlike the diaphragm, the cap can safely remain in the vagina for up to 48 hours (twice the time limit for a diaphragm), so it can be inserted well in advance of intercourse. The cap is rarely associated with urinary tract infections, and no documented cases of toxic shock syndrome have been reported.

Disadvantages of the Cervical Cap. The following are disadvantages of the cervical cap:

Failure rate with any cap is high in women who have given birth (40%). In general, the FemCap has a higher risk for failure than either the diaphragm or the Prentif cap.

Unlike the diaphragm, the cap cannot be used during menstruation.
Use of the cervical cap (particularly the Prentif cap) poses a higher risk for abnormal cervical cell growth than with the diaphragm.
Female Condom

The female condom (Reality, Femidom) is a lubricated, loose-fitting pouch that lines the vagina. It is designed to create a physical barrier against sperm and sexually transmitted diseases by surrounding the penis during intercourse. The failure rate for the female condom is about the same as for the diaphragm and cervical cap. It is available without a prescription but may be hard to find.

Use and Insertion of the Female Condom. The female condom is about 3 inches wide and 6 - 7 inches long (larger than a male condom), with a flexible ring at both ends. Current products are made of polyurethane.

The ring at the closed end is used to insert the device into the vagina and hold it in place over the cervix.

The ring at the open end remains outside the vagina and partly covers the labia (lips).

The insertion process may seem difficult at first but becomes much easier with practice:

The female condom is inserted by hand into the vagina up to 8 hours before intercourse. (It should never be used in combination with a male condom.)
Although the female condom is prelubricated, extra lubricant is sometimes needed while inserting the device or during intercourse. (It is not made of latex, so oil lubricants will not harm it.)

During intercourse, the woman checks to be sure that the outer ring is lying flat against her labia and then guides her partner's penis into the ring.
The female condom should be removed in the following circumstances:

If it tears during insertion or use
If the outer ring is pushed inside
If it bunches up inside the vagina
The female condom may be the best option for women at risk for sexually transmitted diseases and who are not certain that their male partner will use a condom. There are virtually no obstacles against its use except a negative psychological perception. It is not completely fail-proof against pregnancy or sexually transmitted diseases.

Advantages of the Female Condom. In one study, 75% of the women preferred the female to the male condom. Many men also find it more appealing than the latex male condom. The female condom has a number of advantages over the male condom:

The female condom is an effective barrier to viruses, including HIV, and other sexually transmitted organism, particularly since it covers a large area, including external genitals. However, there are few clinical studies at this time to determine its protection against sexually transmitted diseases. No contraceptive device is foolproof.

The standard female condom is made of polyurethane, which is thin and soft but at the same time 40% stronger than the latex male condoms. Polyurethane is not damaged by lubricating oils, as latex is and is also less likely to cause an allergic reaction. It transmits body heat better than latex, providing a more "natural" sensation, and possibly enhancing the pleasure of the sexual act.
The man does not have to withdraw his penis immediately after ejaculation, as is the case with the male condom, but can, if he wishes, withdraw after he has lost his erection.

Disadvantages and Complications of the Female Condom. Compliance rates are low for many reasons. About 25% of women have difficulty on the first attempt at self-insertion. Some women are distressed by self-insertion. The inner ring may be uncomfortable for some women (in which case it can be removed). Some couples complain that the female condom is unpleasant to look at and can be noisy during intercourse. Without sufficient lubrication, it can also be pushed out of place by the penis. Using more lubricant can help keep the female condom in place and reduce the noise. Female condoms are also expensive, and some women wash them out and reuse them to save money. (In such cases, they should be disinfected first and then washed carefully.) Repeated washings can increase the risk for damage and holes. It is not known how many rewashings are safe.

The Sponge
The sponge (Today, Protectaid) is a disposable form of barrier contraception. It is made of soft polyurethane, is round in shape, and fits over the cervix like a diaphragm, but is smaller and easily portable. In 1994, the popular OTC contraceptive was taken off the U.S. market because of problems at the company's manufacturing facility. A new company has since acquired the rights to manufacture the sponge, and has been selling it in Canada and online since 2003. In April 2005, the FDA granted re-approval for the Today sponge to return to the U.S. market.

Use and Insertion. To use the sponge, the woman first wets it with water, then inserts it into the vagina with a finger, using a cord loop attachment. It can be inserted up to 6 hours before intercourse and should be left in place for at least 6 hours following intercourse. The sponge provides protection for up to 12 hours. It should not be left in for more than 30 hours from time of insertion.

The sponge should not be used during menstruation, after childbirth, miscarriage, or termination of pregnancy, or by women with a history of toxic shock syndrome.

Advantages. Because the sponge is not felt during intercourse and can be inserted up to 6 hours before intercourse, it encourages spontaneity. It appears to protect against cervical gonorrhea and Chlamydia.

Disadvantages. Failure rates (about 10%) are higher than with the diaphragm. There is a very small risk for toxic shock using the sponge, as there is for other barrier methods of contraception. The sponge may increase the risk for candidiasis (yeast infection). People who are allergic to spermicides should not use the sponge. The sponge does not protect against HIV or sexually transmitted diseases outside the cervix. The Today sponge contains 10 times the amount of the spermicide nonoxynol-9 than other products, and there is some evidence that this spermicide may increase the risk for HIV. The Protectaid sponge, available in Canada, contains a mix of three spermicides (nonoxynol-9, sodium cholate and benzal konium chloride).

Lea Shield
The Lea shield is made of silicone, and its cup-shaped bowl completely surrounds the cervix without resting on it. The shield does not need to be fitted, and is as effective as the diaphragm and cap when used with spermicide. Its advantages are:

One size fits all
Can be left for 48 hours after intercourse
Reusable for 6 months
The Male Condom
The condom is still the only reversible form of male contraception currently available.

Pregnancy Protection. The condom should be put on before intercourse when the penis is erect, long before ejaculation, since the male can discharge sufficient semen to cause pregnancy before ejaculation occurs. The average rate of pregnancy for couples that rely only on condoms for protection is high -- about 12%. In adolescents the risk of pregnancy with condoms is even higher, 18%. Even for those who use a good-quality condom correctly, the annual risk for pregnancy is 3%.

Prevention of Sexually Transmitted Diseases. Condoms are important in the prevention of sexually transmitted disease in both male and female partners, but they have limitations. They are more protective in men against fluid-transmitted infections (gonorrhea, Chlamydia, trichomoniasis, and HIV) than in preventing infections transmitted by skin-to-skin contact (herpes simplex virus, human papilloma virus, syphilis, and chancroid). Male condoms, in fact, offer better protection against herpes for women than they do for men. (Men often shed the virus from the skin of the penis, which is covered by the condom. In women the virus is often shed from areas around their genitals, which can contact male skin outside the condom.)

Some condoms come pre-lubricated with the spermicide nonoxynol-9, which is no longer recommended with condoms because of a higher risk for HIV infection. Its use in male condoms also promotes yeast and urinary tract infections in women. Other condoms come pre-lubricated without spermicide. Lubricants can also be purchased and applied separately. Only water-based lubricants (K-Y Jelly, Astroglide, AquaLube, glycerin) should be used with latex condoms. Do not use petroleum jelly or other oil-based lubricant products as these can damage the condom. In general, it's best to use a pre-lubricated condom or to apply a water-based lubricant. Unlubricated condoms may injure vaginal tissue and make it vulnerable to infections.

Condom Materials.

Latex. Condoms made of latex rubber are the most common types. They are less likely to slip or break than those made of polyurethane, and they are contoured for a better fit that can provide fairly effective protection. Some people are allergic to latex, however, and in some cases the reaction can be very dangerous. The latex smell may also be unpleasant for some people.

Polyurethane. Polyurethane condoms (Avanti, eZ-on) are also available. It is hoped that eventually they will prove to be superior to latex in a number of ways, including strength, sensitivity, and durability. At this point, they have good acceptance by couples but have a higher breakage rate (6 - 7.2%) compared to the latex condom (1.1 - 2%). Other synthetic materials are under investigation.
Animal Membranes. Condoms made from animal membrane (such as lambskin) can prevent pregnancy, but they are permeable and do not protect against sexually transmitted infections.

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