Barrier contraceptives provide a physical or chemical barrier to block sperm from passing through the cervix into the uterus and fertilizing the egg. Examples of barrier contraceptives include:
- Condoms, which are the only type of contraception that protects against some sexually transmitted infections (STIs)
- Diaphragms and cervical caps
Spermicides are sperm-killing substances available as foams, creams, gels, films, or suppositories. They are typically used along with another barrier device. Diaphragms and cervical caps require the application of a spermicide to be effective. The sponge comes pre-applied with a spermicide. Some condoms come pre-lubricated with spermicide.
When used alone, the spermicide is inserted into the vagina within 30 minutes of sexual intercourse and must be reapplied every time you have sex.
Spermicides are relatively inexpensive and can be purchased at a drugstore without a prescription. 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). They are not recommended as a primary form of birth control.
Spermicides have several disadvantages:
- Nonoxynol-9, the chemical in U.S.-made spermicides, does not provide any protection against sexually transmitted diseases. In fact, frequent use of nonoxynol-9 can cause vaginal and rectal irritation and abrasions that may increase the risk for HIV transmission in women.
- Use of a spermicide with a barrier device may increase the risk for a urinary tract infection in women.
- Condoms that come pre-lubricated with spermicide are not recommended. Research indicates that the spermicide does not make them any more effective than condoms without spermicide. Spermicidal lubricated condoms expire faster than those without spermicide. Non-spermicidal lubricated condoms are safe to use and are a better choice.
The condom is the only type of birth control that protects against some sexually transmitted diseases (STDs) including HIV, the virus that causes AIDS.
The male condom is a thin sheath that is rolled onto an erect penis. It is about 82% effective with typical use.
Male condoms are available in different materials:
- Latex (rubber)
- Polyurethane (plastic)
- Animal membrane (usually lambskin)
Latex condoms are the most common. They are less likely to slip or break than condoms made of polyurethane. Polyurethane condoms are recommended for people who are allergic to latex or who find the smell of latex unpleasant. Condoms made from animal membrane (such as lambskin) can prevent pregnancy, but they are permeable and do not protect against sexually transmitted infections.
Most condoms come pre-lubricated. 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 they can damage the condom.
- It is 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. Unlubricated condoms are also more likely to break.
The female condom is a thin 7-inch lubricated pouch made of polyurethane. It comes with a ring at both ends:
- 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 female condom offers effective protection against pregnancy and STIs. It can be inserted up to 8 hours before sex, but is visible outside of the vagina. Some women have difficulty with the insertion. Female condoms are more expensive than male condoms and (like male condoms) can only be used once.
The diaphragm 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. A diaphragm is usually used along with a spermicide.
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.
Diaphragms come in different sizes and require a prescription and fitting by a health care provider. 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 to 2 years.
Using the Diaphragm
The diaphragm can be placed in the vagina up to 1 hour before intercourse:
- Before or after each use, hold the diaphragm up to the light and fill it with water to check for holes, tears, or leaks.
- Place a small amount of spermicide (about 1 tablespoon) inside the cup, and smear some around the lip of the cup.
- Fold the diaphragm in half and insert it into the vagina by hand or with the assistance of a plastic inserter. Feel to make sure it covers the cervix.
- If you have intercourse again or more than 6 hours after inserting the diaphragm, insert some more spermicide using an applicator.
- The diaphragm must remain in the vagina for at least 6 hours after the final act of intercourse. It should not stay in place for more than 24 hours and should not be used during menstrual periods.
- The diaphragm should be washed with soap and warm water after each use and then dried and stored in its container.
Advantages of the Diaphragm
The diaphragm can be inserted up to an hour before intercourse begins, and usually (although not always) cannot be felt by either partner. It does not interfere with a woman's hormones.
Disadvantages of the Diaphragm
Some disadvantages are:
- The diaphragm is about 85% effective with typical use.
- The diaphragm can be dislodged during sex.
- The spermicide used on the diaphragm may cause irritation to the vaginal lining, which increases the risk of STIs.
- Frequent urinary tract infections and vaginal infections are a problem for some women. Be sure to urinate before inserting the device and after intercourse.
- Women who have a history of recurrent urinary tract infections, toxic shock syndrome, or allergies to latex should not use the diaphragm.
The cervical cap (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 3 sizes (small, medium, large). The cap requires a prescription, pelvic examination, and fitting by a provider.
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. Caps wear out and should be replaced every 1 to 2 years. A refitting may also be needed when a woman experiences certain changes in her health or physical status.
The cervical cap is similar to the diaphragm in terms of most advantages and disadvantages. The cap must stay in place for at least 6 hours, and not be left in place for more than 48 hours.
Rates of effectiveness depend on whether or not a woman has had children:
- For women who have never been pregnant or given birth vaginally, the cap is about 86% effective with typical use.
- For women who have given birth vaginally, the cap is about only 71% effective with typical use.
The sponge is a disposable form of barrier contraception. It is made of soft polyurethane foam coated with spermicide, is round in shape, and fits over the cervix like a diaphragm, but is smaller and easily portable. The Today sponge is the only brand of contraceptive sponge available in the United States.
To use the sponge, first wet it with water, and then insert it into the vagina with a finger, using the nylon cord loop attachment. The sponge can be inserted up to 24 hours before intercourse and should be left in place for at least 6 hours following intercourse. It should not be left in for more than 30 hours.
The sponge should not be used during menstruation. It should not be used soon after childbirth, miscarriage, or termination of pregnancy. Women who have had toxic shock syndrome should not use the sponge.
The sponge contains the spermicide nonoxynol-9, which may increase the risk for vaginal irritation and transmission of HIV.
For women who have never given birth, the sponge is about 88% effective with typical use. For women who have given birth, it is only about 76% effective.