Never have Americans had more choices available for birth control, and even more will soon be on the market. Yet despite the widespread availability of contraceptives, and contraceptive techniques, it’s estimated that at least 50% of all U.S. pregnancies are unintended. Why?
“About half of those unplanned pregnancies are due to failures of the particular birth control method used,” says Kathy A. King, MD, Assistant Professor of Obstetrics and Gynecology at the Medical College of Wisconsin. “The others are because women or their partners are not using any form of contraception at all.”
According to the U.S. Food and Drug Administration (FDA) publication “Protecting Against Unintended Pregnancy: A Guide to Contraceptive Choices,” approximately 10-15% of all sexually active women use no birth control, and about 85% of them would be expected to become pregnant within a year. If used correctly, most of today’s over-the-counter and prescription contraception methods are between 75% and 99% effective, says the FDA.
The choice of birth control depends on a variety of factors, Dr. King says. These include individual health, how often people have sexual relations, the number of partners they have, and if and when they want to have children. In addition, issues such as religious and/or moral belief systems may come into play.
Here is an overview of traditional, over-the-counter, barrier and surgical contraception methods, with the estimated effectiveness of each – assuming they are used correctly. Prescription contraceptive measures including birth control pills, intrauterine devices (IUDs) and injectable hormones will be discussed in Update on Contraception, Part 2 in an upcoming issue of HealthLink.
Traditional Methods
Abstinence. Generally, people who choose to avoid sexual intercourse are said to be practicing abstinence. Those who avoid sexual intercourse and other forms of sexual intimacy are typically said to be practicing celibacy.
Fertility Awareness. Also known as natural family planning or periodic abstinence, this method requires close observation of the woman’s body temperature and other signs of fertility in order to be effective. The woman either abstains from sexual intercourse or uses a barrier method of birth control on the days of a her menstrual cycle when she is more likely to become pregnant. Depending on the method used, the FDA gives this option an effectiveness estimate of about 75%.
Because a sperm may live in the female's reproductive tract for up to seven days and the egg may remain fertile for about 24 hours, a woman could get pregnant from intercourse that occurred from seven days before ovulation to 24 hours or more after. Methods to approximate when a woman is fertile are usually based on the menstrual cycle, changes in cervical mucus, or changes in body temperature.
Withdrawal. In this method, also called coitus interruptus, the man withdraws from the woman before ejaculation. Fertilization of the woman’s egg is prevented if the males sperm don't enter the vaginal canal. This method does not provide protection from STDs, since infectious diseases can be transmitted by direct contact with surface lesions or by pre-ejaculatory fluid. The effectiveness of this method depends on the male's ability to withdraw before ejaculation.
Over-the-Counter Barrier Methods
Male condom. “Everyone can use condoms,” Dr. King says. “And they’re a good choice for anyone who’s not in a mutually monogamous relationship. They’re cheap, portable and readily available.”
Condoms used with a vaginal spermicide are even better at preventing pregnancy, she adds. “And if they’re used correctly, condoms with spermicide are almost as effective as the birth control pill.” (The FDA says The Pill is 95% effective in actual use.)
Some condoms are pre-lubricated. Non-oil-based lubricants, such as water or K-Y jelly, can be used with latex or lambskin condoms, but oil-based lubricants, such as petroleum jelly (Vaseline), lotions, or massage or baby oil, should never be used with condoms: oils can weaken the condom and cause it to break. Lubricants do not increase birth control or STD protection. Estimated effectiveness is 86%.
Condoms, which can be purchased at drugstores and in many supermarkets without a prescription, have an added benefit: They are the most effective contraceptive method for reducing the risk of infection from the viruses that cause AIDS, other HIV-related illnesses and other sexually transmitted diseases, or STDs. For people who are sensitive to latex, polyurethane condoms are a good alternative. Condoms are intended for one-time use.
Female condom. Although some people consider them awkward to use at first, female condoms remain a viable choice, especially for women whose partners are not using condoms. Like the male condom, it provides protection against STDs, is available without a prescription and is intended for one-time use. It should not be used together with a male condom because they may slip out of place. Estimated effectiveness is 79%.
The Sponge. The Today® sponge, a disk-shaped polyurethane device containing a spermicide, is currently not on the market but may be sold again in the future. “Lots of women loved it, but the FDA saw some problems at the manufacturing plant, so the company shut down production, at least for now,” Dr. King says. The sponge, which did not require a prescription, protected for up to 24 hours and for multiple acts of intercourse within this time. The FDA estimates its effectiveness at 60 to 80% in actual use among women who’ve never had children, and 80 to 90% in women who’ve given birth. “The manufacturer refutes these findings,” Dr. King notes. “It claims worldwide data show the sponge is equally effective in all women, regardless of childbearing history.”
Vaginal Spermicides Used Alone. Vaginal spermicides are available without a prescription in foam, cream, jelly, film, suppository or tablet forms. All types contain a sperm-killing chemical, which may also help prevent gonorrhea and chlamydia. Package instructions must be carefully followed because some spermicide products require the couple to wait 10 minutes or more after inserting the spermicide before having sex. One dose of spermicide is usually effective for an hour. For repeated intercourse, additional spermicide must be applied. After intercourse, the spermicide has to remain in place for at least six to eight hours to ensure that all sperm are killed. The woman should not douche or rinse the vagina during this time. Estimated effectiveness is 74%.
Prescription Barrier Methods
Cervical Cap and Diaphragm. Both the cervical cap and the diaphragm are available only by prescription and must be sized by a health professional to achieve a proper fit. Both are made of rubber and must be used with a spermicidal cream or jelly and placed around the cervix just before intercourse. The FDA estimates the effectiveness of the cap at 60 to 80%, and the diaphragm at 80%.
“The cap is not widely used in the Midwest,” Dr. King says. “Sizing is more difficult, so it’s difficult to get a good fit. And the failure rate in women who have had children is greater.” Fewer than 2 percent of women choose diaphragms, she said. “Users tend to be women, typically married women, who can’t or prefer not to be on The Pill.” With both methods, the spermicide may give some protection against two STDs, chlamydia and gonorrhea. A diaphragm protects against pregnancy for six hours after it is inserted. For intercourse after the six-hour period, or for repeated intercourse during that time, fresh spermicide should be placed in the vagina with the diaphragm still in place. The diaphragm should be left in place for at least six hours after the last intercourse but not for longer than a total of 24 hours because of the risk, although low, of toxic shock syndrome (TSS), a rare but potentially fatal infection.
The cervical cap protects for 48 hours and for multiple acts of intercourse within this time. Wearing it for more than 48 hours is not recommended because, like the diaphragm, it has a low risk of TSS.
Surgical sterilization
Male sterilization. Called a vasectomy, this procedure involves surgically sealing, tying or cutting a man's vas deferens, which otherwise would carry the sperm from the testicle to the penis. The 30-minute outpatient surgery can occasionally cause minor postsurgical complications, such as bleeding or infection
Female sterilization. Female sterilization, or tubal ligation, blocks the fallopian tubes so the egg can't travel to the uterus. Sterilization is done by various surgical techniques, usually while the patient is under general anesthesia.
Sterilization is an option for people who are sure they don't want to have children in the future. It is considered permanent because reversal requires major surgery that is not guaranteed to be successful. Complications from these operations are rare but can include infection, ectopic pregnancy, hemorrhage or problems related to the use of general anesthesia.
Update on Contraception, Part 2 discusses oral contraceptives (“The Pill”), intrauterine devices (IUDs) and implantable progestins (Norplant).
