METHODS AND EFFECTIVENESS
Contraception is defined as the avoidance of conception by either natural means (abstinence) or artificial means (physical barriers, chemicals, hormones). Pregnancy can be prevented by interfering with the process of conception at any number of sites in the male or female anatomy.
Barrier methods. A male condom, or prophylactic, is a thin sheath made to fit an erect penis. It can be made of latex (a type of rubber), polyurethane (a type of plastic), or natural products such as lamb’s intestines. A condom prevents semen, which contains sperm, from entering a woman’s vagina during intercourse. The latex or polyurethane condom is one of the few forms of contraception that can also protect against sexually transmitted diseases (STDs). Men who are not allergic to latex should use latex condoms, as they are the best at preventing pregnancy and STDs. Polyurethane condoms break more easily, and natural condoms are not as effective at preventing STDs.
Male condoms should be used any time a man has intercourse with his partner and desires to prevent STDs or pregnancy. If the condom does not have space at the end, called a sperm repository, then 0.25 inches of the condom should be left at the tip of the penis to collect semen. To increase the protective birth control value, spermicidal foam or jelly can be used in addition to the condom. According to the American College of Obstetricians and Gynecologists, this combination is 99 percent effective. Vaseline or other types of petroleum jelly, lotion, or oils should not be used as lubricants with condoms because they weaken the latex rubber. Non-oil-based lubricants or even water can be used with latex condoms. Condoms come in various sizes and can be purchased over the counter at drugstores, pharmacies, and coin machines in many public restrooms. There is no age restriction on buying condoms.
Some Types of Contraceptive Devices
Many different kinds of devices have been designed to prevent pregnancy, from barrier methods such as condoms and diaphragms to hormonal methods such as birth control pills. Each method has its own advantages, disadvantages, and failure rates.
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The female condom is a lubricated, thin polyurethane or nitrile tube that has a flexible ring that facilitates insertion and an outside ring that helps keep the condom in place around the vulva. The closed end of the tube is inserted into the vagina, and the other end remains outside the vagina, slightly covering the labia and providing some enhanced protection against skin-borne infections. With proper use, the female condom is similar to the male condom in effectiveness, and it may be more accepted by male partners who do not wish to wear a condom. Female condoms, however, are more expensive and harder to find. The recent introduction of a new nitrile female condom, FC2, has lowered the price, and many public health and reproductive health advocates are working to make the method more accepted and widely available. Like the male condom, the female condom should be used only once per intercourse, and female and male condoms should not be used together.
A diaphragm is a dome-shaped rubber disk with a flexible rim covering the cervix so sperm cannot enter the uterus. A diaphragm, which must be prescribed and sized by a health care professional, is designed to be used with a spermicide that is applied inside the dome and around the rim. The diaphragm provides birth control protection up to six hours after insertion. A new application of spermicide should be inserted into the vagina with an applicator and with the diaphragm in place for repeated intercourse. To be effective, the diaphragm must remain in the vagina six hours after the last intercourse but never longer than twenty-four hours because of the risk of toxic shock syndrome. The diaphragm is approximately 83 percent effective as a birth control method.
The cervical cap is a soft rubber or plastic cup with a round rim, which fits snugly over the cervix. As with a diaphragm, it must be fitted by a healthcare professional. The cervical cap should be combined with a spermicidal cream or jelly for optimal effectiveness. It can provide birth control protection for up to forty-eight hours. The cervical cap should be removed after forty-eight hours because of a low risk of toxic shock syndrome. It does not provide any protection against STDs.
Vaginal spermicides include creams, jellies, films, foams, suppositories, and tablets. They contain sperm-killing chemicals and act somewhat as a barrier to sperm entering the uterus. Spermicides used by themselves are up to 79 percent effective for birth control, but when used properly with condoms, they are up to 99 percent effective. They are available without a prescription. For spermicides to be effective, they should be inserted into the woman’s vagina up to twenty minutes before intercourse and stay in the vagina for at least eight hours. A new application of spermicide should be applied for repeated intercourse. Spermicides do not protect against STDs unless they are used in combination with condoms.
Hormonal methods. Oral contraceptives or birth control pills, often called “the pill,” are the most popular form of reversible birth control in the United States. They contain synthetic hormones that interact with a woman’s natural hormones to prevent pregnancy. There are two types of birth control pills: combination estrogen-progestin and progestin alone.
Combination birth control pills stop the ovaries from releasing eggs. Available only by prescription, combination pills come in packages of twenty-one or twenty-eight pills per month. However, there are new pills designed for continuous or extended cycling that come in packages with more than a month’s supply. There are twenty-one active pills in the twenty-one-day pack. The twenty-eight-day pack contains twenty-one active pills and seven placebo or sugar pills, except for some newer formulations that extend the active pill cycle to more than twenty-one pills, reducing the number of inactive or placebo pills. Menstruation occurs during the week with no pills or inactive pills. However, extended or continuous cycling involves a longer or continuous regimen of active pills and delays menstruation until a pill-free interval.
Some other forms of contraception should be used for the first month in addition to the birth control pill. By the second month, the pill should provide the needed birth control. Pills should be taken at the same time of the day each day. Oral contraceptives are 98 to 99 percent effective in providing birth control, but they do not protect against STDs. Oral contraceptives can be taken safely by most women, but they are not recommended for women over thirty-five who smoke. A benefit of oral contraceptives is that they can make a woman’s menstrual cycle regular and lighter, and they are protective against pelvic inflammatory disease (PID), ovarian cancer, and endometrial cancer.
The second form of oral contraception is the mini-pill. It contains only one hormone, progestin, and works by thickening the cervical mucus so that sperm cannot reach the egg. Progestin also changes the lining of the uterus so that implantation cannot occur. Mini pills are 95 percent effective in preventing pregnancy, but their effectiveness diminishes if they are not taken on time. A pill taken more than two hours from the set time for a daily dose constitutes a missed pill and significantly raises the chance of unintended pregnancy.
Ortho Evra is a thin patch that releases estrogen and progestin. It is worn on the upper outer arm, upper torso (excluding the breast), buttocks, or abdomen. Once attached, it delivers hormones through the skin and into the bloodstream. The patch will remain in place during exercise or bathing and in humid conditions. It is worn for three weeks, then removed for one week before a new patch is worn. The patch offers approximately 99 percent birth control protection but no protection from STDs. It is significantly less effective in women weighing more than 198 pounds.
NuvaRing is a transparent flexible ring that is inserted into the vagina and normally stays around the cervix. The ring releases estrogen and progestin into the vagina to stop ovulation, to thicken cervical mucus, and to prevent implantation if fertilization occurs. The ring is worn for three weeks, followed by a week off, during which menstruation occurs. Vaginal rings must be replaced each month. If the ring slips out of the vagina, the patient can wash the ring with cold to lukewarm water (avoiding hot water) and reinsert it. The chance of pregnancy is increased if the ring is outside the vagina for more than three hours; if this occurs, the woman should use a backup method for another seven days to obtain maximum protection against pregnancy. Both NuvaRing and Ortho Evra share the same contraindications and benefits as combined oral contraceptives.
Depo-Provera (depo-medroxyprogesterone acetate, or DMPA) contains only the hormone progestin and is given by a healthcare provider as an injection every twelve weeks. DMPA comes in two formulations and can be given by intramuscular or subcutaneous injection. Patients need to be aware that irregular bleeding (which may include brownish spotting) and probable lack of normal menses are expected side effects of DMPA, not signs of a serious adverse effect. For some women who discontinue using DMPA, delayed fertility can last up to one year beyond the end of the injections. DMPA works in the same way as the mini-pill.
Those who use DMPA should be cautious, as both adolescents and adults have experienced a significant loss of bone density. This bone loss is thought to correct itself when the injections are discontinued, except women in perimenopause may not have enough time to reclaim bone mass before menopause. Furthermore, DMPA leads to weight gain in some women through increased appetite. Women should be cautioned against overeating once beginning DMPA as their birth control method.
Emergency contraceptive pills can be used after a sexual assault, after intercourse without contraception, after finding that a condom broke during or after sex, or after the failure of some other method. Emergency contraception can be performed through a progestin-only formulation that involves taking two pills as soon as possible after unprotected sex but within seventy-two hours (based on strong evidence, some clinical practices recommend emergency contraception as effective for up to five days after unprotected intercourse). A woman should have her menstrual cycle within ten to twenty-one days of taking emergency contraception pills, and after that, her cycle should return to normal. These pills prevent conception, rather than causing a miscarriage, by thickening the cervical mucus, thus preventing sperm from fertilizing the egg. In 2003, a Food and Drug Administration (FDA) panel recommended that these morning-after pills, as they came to be known, be made available over the counter. They initially became available over the counter to girls and women seventeen years of age and older. Girls under the age of seventeen needed a prescription from a healthcare provider to obtain emergency contraception. In 2011, the FDA was ready to lift this age restriction but was blocked by Secretary of Health and Human Services Kathleen Sebelius. When a federal judge ordered the FDA to certify the drug for nonprescription use in 2013, the Obama administration initially tried to block the order before deciding to drop its appeal. On June 20, 2013, the FDA approved Plan B One-Step (levonorgestrel) as an over-the-counter emergency contraceptive without age or point-of-sale restrictions.
Additional but less widely used methods of emergency contraception include the Yuzpe method, involving high doses of combined oral contraceptives and insertion of an IUD following unprotected intercourse.
Intrauterine devices (IUDs). The IUD is a small device that is inserted into a woman’s uterus by a health care provider in a simple office procedure. Two IUDs are currently available in the United States. Both are shaped like a capital T and have a silky or plastic thread extending into the cervix, allowing easy removal. The ParaGard T 380A contains copper but no hormones and can be kept in the uterus for ten years. Mirena is an IUD that contains a progestin that releases slowly throughout the time that the device is in place. It can be kept in the uterus for five years. While ParaGard may result in some increased bleeding, a woman will have regular menses. Mirena greatly decreases menstrual flow but can result in irregular spotting, especially in the first three months of insertion, and some women stop having menses altogether. An IUD is thought to prevent pregnancy because it is a foreign object whose presence causes the woman’s uterus to function improperly. The IUD interferes with sperm reaching the egg and prevents the egg from implanting in the uterus. IUDs that contain copper are thought to work by releasing copper ions into the uterus. The copper in the uterine cavity stops sperm from moving through the vagina and into the uterus. IUDs are 97 to 99 percent effective in preventing pregnancy but do not protect from STDs.
Sterilization. Male sterilization through vasectomy can be performed in a doctor’s office. Local anesthesia is applied, and a small incision is made in the upper part of the scrotum. The vas deferens are cut and sealed. This simple operation prevents sperm from traveling out of the testes. There is also a nonsurgical technique in which the doctor locates the vas deferens and holds them in place with a small clamp. A tiny puncture is made in the skin, and the opening is stretched so the vas deferens can be cut and tied. This procedure requires no stitches because the punctures heal quickly on their own. With either of these methods, a man can return home immediately after the procedure and usually needs only a day of rest before resuming his normal activities. It is recommended that another form of birth control be used during the first nine or ten ejaculations to ensure that the seminal fluid no longer contains sperm. This method is 99 to 100 percent effective in preventing pregnancy; however, it does not protect against STDs.