Article updated and reviewed by Christina S. Chu, MD, Assistant Professor, Department of Obstetrics and Gynecology, Division of Gynecologic Oncology, University of Pennsylvania on May 10, 2005.
Contraception is the use of artificial or natural means to prevent conception, or pregnancy.
Types of Contraception
There are various contraceptive methods available today. The most common artificial methods are male/female condoms, spermicides, sponge, diaphragm, cervical cap, oral contraceptives (birth control pills), injectable contraceptives (Depo-Provera, Lunelle), vaginal rings, intrauterine devices (IUDs) and surgical sterilization.
The natural methods include complete abstinence (no sexual intercourse), periodic abstinence and withdrawal.
Emergency contraception is a method to prevent pregnancy after unprotected intercourse has occurred.
The male condom (also known as a prophylactic or rubber) is a thin sheath, usually made of latex rubber, which covers the erect penis. When used correctly, a latex condom is about 85 percent effective, both for preventing pregnancy and decreasing the chance of contracting most STDs, including AIDS. Condoms can also be made of animal membrane; however, some experts believe that the pores in such natural "skin" condoms may allow the virus to pass through. To be effective, condoms must be undamaged, applied to the erect penis before any genital contact, and must remain intact and snugly in place until completion of the sexual activity. After intercourse is completed, the edges of the condom should be held up to prevent spilling semen when the penis is withdrawn from the vagina.
The female condom is a lubricated sheath with a flexible polyurethane ring on each end. One ring is inserted into the vagina while the other remains outside. The ring outside covers the labia and keeps the condom in place during intercourse. When in place, the vaginal condom lines the vaginal wall and creates a covered passageway for the penis. To be effective, the condom must be undamaged and inserted before any genital contact. It must also remain inside of the vagina until the completion of intercourse. The estimated effectiveness of the female condom is 74 to 79 percent.
Risks and side effects: The risks of using a male or female condom are minimal. Some people can experience a slight irritation and allergic reaction.
Spermicides are available in foam, jelly, gel and suppositories, and work by forming a physical and chemical barrier to sperm. They can be inserted into the vagina on a diaphragm, a cervical cap, a condom, or alone, within an hour before sexual intercourse. If intercourse is repeated, more spermicide should be inserted. The estimated effectiveness is about 70 to 80 percent.
Risks and side effects: The risks of using spermicides are minimal. Some people can experience a slight irritation and allergic reaction.
The sponge is made of white polyurethane foam (shaped like a small donut) and contains a spermicide. The sponge is inserted into the vagina to cover the cervix during and after intercourse. It is held in place by the vaginal walls and the dimple covering the cervix. The estimated effectiveness is 72 to 82 percent.
Risks and side effects: The risks of using a sponge are minimal. Some people may experience a slight irritation and allergic reaction, difficulty in removal, and very rarely, toxic shock syndrome (a bacterial infection associated with the use of highly absorbent tampons).
A diaphragm is made of soft rubber and is shaped like a shallow cup. It has a flexible metal spring rim that fits snugly over the cervix. Before insertion, a spermicidial cream or jelly should be applied into the shallow cup. The diaphragm must be fitted by a health professional and the correct size must be prescribed to ensure a snug seal with the vaginal wall. The estimated effectiveness is 82 to 94 percent.
Risks and side effects: The risks of using a diaphragm are minimal. Some people may experience a slight irritation, an allergic reaction, a bladder infection and very rarely, toxic shock syndrome (a bacterial infection caused by use of highly absorbent tampons).
Women who have a severely displaced uterus, cystocele (a protrusion of the bladder through the vaginal wall), fistulas (openings in the vagina), scoliosis (curvature of the spine), spina bifida, chronic urinary tract infections or a history of toxic shock syndrome, should not use a diaphragm.
The cervical cap is a thimble-shaped rubber cap that fits snugly over the cervix. Like the diaphragm, it blocks sperm from entering the cervical opening. Usually, a small amount of spermicide is used on the inside of the cap to kill any sperm that may break through the seal. The cervical cap must be fitted by a health professional and the correct size prescribed to ensure a snug seal. It has an estimated effectiveness of about 82 percent.
Risks and side effects: The risks of using a cervical cap may include abnormal pap tests, vaginal or cervical infections, and very rarely, toxic shock syndrome.
Women who have a severely displaced uterus, fistulas, scoliosis, spina bifida, chronic urinary tract infections, a history of toxic shock syndrome, cervical erosion or laceration, or an elongated or irregular cervix, should not use a cervical cap.
Oral Contraceptives (Birth Control Pills)
At present, more than 20 brand names and more than twice that number of formulations of oral contraceptives are available. When used correctly and consistently, oral contraceptives are 99 percent effective. With typical use, oral contraceptives are 90% effective.
Birth control pills use synthetic hormones similar to the ones made in the ovaries. There are two types of pills currently manufactured in the United States: a combination pill, with both synthetic progesterone (progestin) and synthetic estrogen; and mini-pills, which contain only progestin.
Although all oral contraceptives prevent sperm from uniting with an egg, they work in slightly different ways. The combination pill keeps the ovaries from releasing an egg. The mini-pill is less reliable in suppressing egg release, but creates changes in the cervix and uterus that make conception less likely.
The mini-pill is less effective than the combination pill, but does not have the risks attributed to estrogen, such as increased possibility of blood clots and nausea. However, the mini-pill causes more problems with spotting and bleeding between periods and therefore, its use is not widespread. Women who are breastfeeding may choose to use the mini-pill rather than combination pills because mini-pills cause less effect on breast milk production.
Combination pills come in two types. One provides the same combined dose of synthetic progestin and synthetic estrogen throughout the entire cycle. Others, sometimes called biphasic or triphasic pills vary the levels of these two hormones to more closely approximate a woman's normal hormonal variations. In some women, these pills have a lower risk of side effects.
The pill essentially works by interfering with a woman's normal fluctuations in hormone levels, which in turn prevents the egg from maturing and being released. It also acts on the climate of the cervix, uterine lining and fallopian tubes, making them all inhospitable for egg, sperm or embryo.
Combination pills are packaged in several ways: the most common is the 21-day pack. One pill is taken each day for 21 days, then none during the next seven days (for the average 28-day cycle during which menstruation occurs). There are also 28-day packs, with 21 active pills followed by seven inactive ones (placebos).
The mini-pills must be taken every day.
In addition to effectiveness in preventing conception, oral contraceptives offer other benefits. Menstrual periods are usually lighter, making iron deficiency less likely, and there may be less cramping. Ovarian cysts, ovarian cancer, and perhaps endometrial cancer occur less often among pill users. In addition, ectopic pregnancy occurs less frequently among pill users (in the rare instance when pregnancy occurs at all). Oral contraception may also help with acne and some cases of unwanted, masculine type hair growth.
Risks and side effects: Minor side effects include headaches, sore breasts, weight gain, feeling sick to your stomach, irregular bleeding, and depression. Serious possible side effects are more likely to occur in women over the age of 35. These include an increased risk of heart attack, stroke and formation of blood clots in the veins (thrombosis). Fortunately, the risk of blood clots has been greatly reduced with the availability of newer lower dose pills. Though still elevated, the risk for suffering a blood clot with the new low dose pills is only about 3 in 10,000 woman-years. Because blood clots are more common in women who smoke, smokers should be carefully counseled about the risks and strongly encouraged to quit. The risk of coronary artery disease is particularly increased in women who smoke, who are overweight, or have high blood pressure or diabetes. Women who take combined oral contraceptive pills may have a slightly increased risk of benign liver problems. Those women who are already at risk for gallbladder problems may find that taking combination pills speeds up the appearance of symptoms.
Some women should not take combined oral contraceptive pills, including:
smokers over the age of 35
those with very high blood pressure (over 160/100)
those with a history of stroke or heart disease
those with complicated heart valve problems
those with a history of diabetes for more than 20 years
those with diabetes complicated by blood vessel disease
those with multiple risk factors for heart disease (e.g., older age, smoking, diabetes, hypertension)
those with current breast cancer, or breast cancer diagnosed within the last five years
those with active liver disease, benign or malignant liver tumors
those with gallbladder problems
those with complicated migraine headaches
breastfeeding women within six weeks of birth (and perhaps those in the first six months of breastfeeding) because estrogen may decrease the milk supply.
Possible Interactions: There is a possibility that the herb St. John’s wort may interfere with the pill’s effectiveness, therefore it is best not to take this herb at the same time that you are on the pill. Certain drugs such as phenytoin or rifampin, and several antibiotics can also interfere with the effectiveness of the birth control pill. It is best to consult with a pharmacist or your doctor to determine if any medication you are taking might interfere with the pill.
Ortho Evra, Contraceptive Patch
The Contraceptive Patch has the same properties as the oral birth control pill, but is applied to the skin of the lower abdomen, buttocks, upper arm or upper body. It is worn continuously for 7 days and then replaced with another patch every week for 3 weeks, followed by one week without a patch. When used as directed, the patch is also about 99% effective.
Risks and side effects: Side effects of the Contraceptive Patch may include nausea or breast tenderness, and rare risks of blood clots, heart attack and stroke, particularly if women smoke while using the contraceptive.
The vaginal ring is a flexible transparent ring about two inches wide that is inserted into the vagina once each cycle. The ring is placed into the vagina and left in place for three weeks, then removed for one week to allow for a period. The ring releases both estrogen and progesterone. When used as directed, the ring is about 99% effective.
Risks and side effects: The risks of the vaginal ring are similar to those for other combination contraceptives, including a rare risk of blood clots, heart attack and stroke, particularly if women smoke while using the contraceptive. In a clinical trial, the main side effects from the ring were headache and vaginal discharge, however women who stopped using the ring complained of being able to sense a foreign object in their vagina, problems during intercourse with the ring in place, having the ring fall out, or having vaginal discomfort. Unlike other combined hormonal methods of birth control, the vaginal ring rarely causes irregular vaginal bleeding.
Depo-Provera is an injectable form of a progestin (like the oral minipill). Each injection provides contraceptive protection for 14 weeks. It is injected every three months into a muscle in the buttocks or arm. Its estimated effectiveness is 99 percent.
Risks and side effects: The risks of using Depo-Provera may include menstrual cycle irregularity, headaches, nervousness, depression, nausea, dizziness, change of appetite, breast tenderness, weight gain, enlargement of ovaries and/or fallopian tubes, excessive growth of body and facial hair.
Lunelle is an injectable form of combined estrogen/progesterone contraception. It is injected each month in the muscle of the arm, thigh or buttock, during or within the first days after your period. It is made to release the hormones such that there is a peak of progesterone and estrogen that gradually decreases until the next injection. Its estimated effectiveness is 99 percent.
Risks and side effects: The risks of using Lunelle may include menstrual cycle irregularity, change of appetite, breast tenderness, and weight gain.
IUDs are small devices that fit inside the uterus. Some contain copper or synthetic progesterone. One or more strings are usually attached to IUDs. When the IUD is in place, these strings extend into the upper vagina. Though doctors are unsure exactly how the IUD works, it is thought that the IUD makes the uterine cavity toxic to sperm and eggs, and prevents implantation of fertilized eggs. IUDs containing progesterone also act by preventing ovulation, making the lining of the uterus thin to prevent implantation, and thickening the cervical mucous to prevent sperm from passing into the uterus. The levonorgestrel containing IUD is the most effective reversible method of birth control available, with a failure rate of about 0.1%.
Risks and side effects: The risks of using IUDs are cramps, bleeding, pelvic inflammatory disease((PID, an infection of the uterus and fallopian tubes), infertility, and very rarely, perforation of the uterus.
IUDs should not be used by women who are pregnant, who have an active/recent or recurrent pelvic infection, acute cervicitis, vaginitis, abnormal pap tests, irregular or abnormal pelvic bleeding, disorders of the blood, endometriosis, exposure to DES in utero, an abortion within the last three months that led to an infection, diabetes, sickle cell anemia, anemia, anemia, bicornuate uterus, cervical stenosis, endometrial polyps, severe menstrual cramps or bleeding, small uterus or valvular heart disease.
Emergency contraception is a method to prevent pregnancy after unprotected intercourse has occurred. It is best used in situations when intercourse happens infrequently or unexpectedly, not as a routine method of birth control. Though there is no apparent harm in giving repeated doses of emergency contraception, the effectiveness is lower than other regularly used forms of birth control, and there is no protection against sexually transmitted disease.
Several methods of emergency contraception are available including oral levonorgestrel (a progesterone), oral combination pills, special doses of regular oral contraceptives, insertion of a copper IUD and mifepristone (RU-486). The most commonly prescribed pills are called Plan B and Preven. Both of these regimens consist of two pills taken 12 hours apart, and are most effective if taken within 72 hours after intercourse, though they may be effective up to five days afterwards.
Risks and side effects: Emergency contraceptive pills can cause nausea, headache, abdominal pain, dizziness and breast tenderness, and can disrupt the regularity of the menstrual cycle.
Mifepristone, or RU-486, is another available method of emergency contraception. Approved in the U.S. in September 2000, RU-486 causes the uterine lining to shed after an egg is implanted. It is taken as a series of pills over the course of a few weeks and will interrupt a very early pregnancy. It is very widely used in Europe and has been approved in the U.S. since September 2000. It is best to have this pill prescribed by a physician or health care setting that is familiar with its use and can follow users carefully to assure optimal outcomes. Initial studies show that RU-486 may be more effective than emergency contraceptive pills like Preven and Plan B, with a failure rate of less than 1%.
Risks and side effects: Possible side effects include weight gain, sore breasts and menstrual cycle irregularity.
Copper IUDs may be inserted up to five days after unprotected intercourse to prevent pregnancy. This method is particularly attractive for those who are not at risk for sexually transmitted infections, and who want to use the IUD for long term contraception. The copper IUD is very effective for emergency contraception, with a failure rate of less than 0.1%.
Risks and side effects: Side effects are similar to those for regular IUDs. Patients may experience cramping and irregular bleeding.
Female sterilization (tubal ligation) involves either cutting, constricting, clipping or cauterizing the fallopian tubes to prevent the male sperm from reaching the ova. Male sterilization (vasectomy) involves cutting the two vas deferens (the ducts that carry sperm from the testes to the seminal vesicles). Tubal ligation is about 95% - 99% effective, with rates varying depending on type of procedure used, and the age at which sterilization occurs.
Risks and side effects: Both of these have the normal risks associated with surgery, including infection or bleeding after the operation.
Complete Abstinence and Periodic Abstinence
Complete abstinence is not engaging in any type of sexual intercourse. Periodic abstinence is not having sexual intercourse during a woman's fertile period. Also called "natural family planning" or the "rhythm method", periodic abstinence is dependent on the ability to identify the approximate 10 days in each menstrual cycle that a woman is fertile. Its estimated effectiveness varies from 53 to 86 percent. However, it is important to recognize that many experts in family planning feel that the actual effectiveness of this method is much lower. This is because many women vary from month to month with respect to when they are most fertile.
Withdrawal involves removing the penis from the vagina just before ejaculation so that the sperm is deposited outside the vagina and away from the lips of the vagina, as well. Withdrawal is not very effective, because the drops of fluid that come out of the penis right after it becomes erect can contain enough sperm to cause pregnancy.
Editorial review provided by VeriMed Healthcare Network.