Information about Barrier Methods of Birth Control
Condoms are usually made of latex rubber and are about 0.065 to 0.085 mm thick. Thinner condoms have been used in Japan for many years, and condoms as thin as 0.020 mm are now available in the United States. Polyurethane condoms are also available. Women whose partner uses a polyurethane condom should check with a health care provider to be sure it provides protection against STDs and HIV.
An important advantage of latex condoms is that they prevent the transmission of HIV and STDs. Condoms also offer protection from cervical dysplasia (a condition that, if left untreated, can lead to cervical cancer).
Although condoms made out of biological products such as lambskin may be effective contraceptives, they do not effectively prevent the transmission of HIV, because HIV can pass through the pores in lambskin.
Condoms should be purchased in a store where the customer is guaranteed product reliability and freshness. Heat, pressure, and age can lead to the degradation and ineffectiveness. Condoms should not be used more than 5 years after the manufacture date. If the condom looks deteriorated, is discolored, or feels sticky or brittle, it should not be used. Likewise, if the package is torn or damaged, the condoms inside should not be used.
Petroleum or oil-based lubricants can degrade latex and should be avoided. Water-based lubricants should be used instead and are usually labeled "for use with latex condoms or diaphragms."
Condoms are easily torn, so care should be taken while putting them on and taking them off. Researchers estimate that condoms break once out of every 115 to 477 acts of intercourse. Tearing usually occurs before ejaculation and is probably caused by too much friction (which can be reduced by the use of lubricants). The failure rate is about 10 to 14 percent.
The Female Condom
The female condom consists of a polyurethane sheath attached to a ring of latex that covers the entire vulva as well as the vagina. Because the sheath is not made of latex, it can be used with a water-based or oil-based lubricant. It has proven effective at preventing the transmission of HIV, though the NIH warns that these condoms are not as well studied as latex condoms. Theoretically, female condoms offer increased protection from STDs as well. It is not yet clear how they affect sensation or how acceptable they will become as a useful method of contraception.
A spermicide is a chemical that kills sperm. Vaginal spermicides are made of a spermicide mixed with a cream, jelly, or foam base. Some spermicides are sold as vaginal suppositories, which are solid at room temperature but melt to liquid at body temperature. Spermicides are not very reliable when used alone (only about 70 to 80 percent effective); they are designed to be used in combination with a condom, diaphragm, or cervical cap.
It is not clear whether they increase the effectiveness of these methods of contraception, although they do serve as a lubricant, making sex more enjoyable and decreasing the risk that a condom will tear from too much friction. The active ingredient in spermicide preparations is non-oxynol-9, otherwise known as as octoxynol.
A diaphragm is a circular, rubber cap-like shield that is put inside the vagina before intercourse to cover the cervix. It is made of a metal spring that is covered with latex. Diaphragms come in several different sizes (from 50 to 90 mm in diameter) and types (coil, flat, or arcing, depending on the the rim of the spring). It is essential that diaphragms be fitted properly, because an incorrect fit can cause discomfort and vaginal ulceration (sores).
It is also important that women insert it correctly, so it covers the cervix and upper vagina. Questions about insertion should be answered by a health care provider.
Diaphragms are always used with spermicides, although it is not at all clear how much extra protection the spermicide provides. The diaphragm can be inserted several hours before intercourse. The diaphragm should not be removed if intercourse is repeated; simply add more spermicide. It should be left in place for at least 6 hours after sex to provide complete immobilization of the sperm.
After the diaphragm is removed, it should be washed with soap and water, allowed to dry, and stored away from heat. Diaphragms should not be dusted with talc because it has been linked to ovarian cancer.
The failure rate for the diaphragm is about 5.5 percent. Disadvantages include an increased risk for bladder infection and cystitis (inflamed urinary bladder). It also has been linked to toxic shock syndrome, a rare, serious illness caused by a bacterial toxin (poison).
A cervical cap is smaller and tighter-fitting than a diaphragm, covering only the cervix. It is harder to fit and takes longer to learn how to use. It can be left in place for up to 72 hours.
Cervical caps are often referred to according to size: a cap 22 mm in diameter is called a No. 22; a cap 25 mm in diameter is a No. 25, and so on. Most women who have never had a child are fitted with a No. 22, and women who have given birth are usually fitted with a No. 25.
Cervical caps are inserted by compressing them between the finger and thumb and placing them through the vagina, dome outward. The cap should be pushed gently up to the cervix and into place. The dome should stay compressed for a few seconds, indicating a gentle fit. The cap should be used with a spermicide and checked to make sure that it has not been dislodged during intercourse. Use of a cervical cap has been linked to toxic shock syndrome, but the risk for cystitis (inflammed urinary bladder) are lower than with a diaphragm. Its failure rate is about 8 percent.
Intrauterine Devices (IUDs)
An IUD is a small piece of metal or plastic that is inserted by a physician through the cervical canal into the uterus. A string remains in the vagina so the woman can make sure the IUD is in place and to allow for easier removal by a physician. IUDs do not protect against HIV or prevent the transmission of STDs.
It is not exactly clear how IUDs interfere with conception. It is generally believed that IUDs interfere with the passage of sperm through the uterus, thus preventing fertilization.
In the early 1970s, the Dalkon Shield (particular type of IUD) was taken off the market because it caused pelvic inflammatory disease and numerous deaths. In 1984, the Food and Drug Administration (FDA) approved second-generation IUDs, which are smaller, more comfortable, and provide better protection against pregnancy.
The Copper T 380A (ParaGard®) is FDA-approved for up to 10 years of continuous use during all stages of reproductive life. This contraceptive device is associated with a pregnancy rate of less than 1 percent. The most common side effects of ParaGard® are pelvic inflammatory disease (PID), ectopic pregnancy (pregnancy that occurs outside the uterus), heavy menstruation, irregular menstrual bleeding, and pelvic pain.
Levonorgestrel-releasing intrauterine systems (Mirena®, Skyla) are long-acting, reversible IUDs that are approved by the FDA. These systems, which are made of plastic and inserted into the uterus, release a low dose of the hormone progestin and are up to 99 percent effective at preventing pregnancy. Mirena can be used for as many as 5 years and is recommended for women who have already had a child. Skyla (available beginning in February 2013) can be used for 3 years and is aimed at women who have not yet had a pregnancy.
Talk to your health care provider. Women who have certain medical conditions, including pelvic infection or a history of some types of cancer, should not use this form of birth control. Side effects include pelvic inflammatory disease, abdominal pain, abnormal bleeding and headache.
Inserting an IUD
During the initial visit to a health care provider, a medical history is taken, a physical examination is performed, and a cervical culture is taken to look for the presence of gonorrhea and chlamydia. Women with IUDs are at an increased risk for developing pelvic inflammatory disease, a painful and serious condition caused by untreated gonorrhea and chlamydia. The woman is also counseled about the risks and alternatives to IUDs.
The IUD is inserted at the second visit and women should avoid having intercourse until then. Some women prefer to have the device inserted during their period. Physicians generally recommend ibuprofen beforehand, to reduce the discomfort of the procedure.
Before the IUD is inserted, the physician performs a pelvic examination to determine the size and position of the uterus. Ultrasound is used to measure the size of the uterine cavity and the IUD is gently inserted through the cervical canal.