Condoms are able to protect you from infections that are transmitted during sexual intercourse. However, they do not protect you from contact with sores or warts on areas of the body that are not covered by the condom or from pubic lice or scabies.

If you choose not to use condoms, you should make sure that neither you nor your partner is carrying an infection. Discuss your past sexual contacts honestly, particularly if either of you is in a high-risk group. If you suspect that you have been exposed to infection, arrange to have a screening test at a clinic that specializes in treating STDs. With HIV infection, there is a latent period of at least 2-3 months between acquiring the infection and the time when the antibody to the virus can be detected in the test. For this reason, many clinics advise using condoms for the first 3 months of a new relationship before having an HIV test.

Once you and your partner are sure that you are free from STDs, the most effective way to protect yourselves is by remaining monogamous. If you do have sexual intercourse with other partners, be sure that you use condoms.

If you are not using condoms and develop an STD, use condoms until you have been treated and are free of disease or abstain from penetrative sex. Both you and your partner should be treated at the same time to avoid the risk of reinfecting each other, and you should both be free of disease before you stop using condoms. Sexual activities that carry a relatively low risk of infection include kissing your partner’s mouth (or body areas other than the genitals) and mutual masturbation by hand. The activities that have little or no risk are those that do not involve contact with your partner’s genitals. These include intimate activities, such as cuddling, massage, and bathing together.

Contraception
Artificial and natural methods for controlling fertility

Contraception allows people to choose whether and when to have children. There are several types and each works differently. Nearly all types, apart from the male condom and male sterilization, are designed for use by women.

Most contraceptives, with the exception of condoms, are supplied by your doctor, who considers your age, medical history, and sexual lifestyle. No contraceptive is entirely free from risk. Some types may not be suitable for you, while others have side effects that you must weigh against the benefits. You may also need to change your contraceptive as you grow older, have children, or alter your sexual lifestyle. It is important that you are happy with your choice of contraceptive. Even if your doctor has recommended a particular type, do not accept it if you have doubts about it.

BARRIER METHODS

Barrier contraceptive methods include diaphragms, condoms, and cervical caps. They act by preventing sperm from entering the uterus and reaching the egg. Male condoms cover the penis, female condoms line the vagina, and caps and diaphragms cover the cervix. Barrier contraceptives do not disrupt normal body functions or affect fertility, but they are unreliable if not used correctly and can also affect the spontaneity of sex. Some people who use condoms may be allergic to the material from which the condom is made.

When used correctly, condoms are an effective method of preventing unwanted pregnancy. Condoms are also thought to protect women from cancer of the cervix by reducing the risk of infection with the human papilloma virus, which has been strongly linked with this type of cancer.

The male condom is the only contraceptive method that also protects users and their partners from STDs and other infections. Condoms may also be used for protection when one partner has a chronic infection such as HIV (see HIV infections and AIDS).

HORMONAL METHODS

Hormonal contraceptives alter the hormone balance in a woman’s body to prevent conception. They may be taken as oral contraceptives in the form of the combined pill or progestin-only pill. Other options are an injection into a muscle (from where the hormone is gradually released) every 2 or 3 months or inserting an implant that releases hormones under the skin. Hormonal methods are useful because they do not interrupt sexual activities, but they can cause side effects or health risks in some women. Oral contraceptives may be less reliable after vomiting or diarrhea or if you are taking some types of antibiotics. For this reason, if you are taking an oral contraceptive, you should tell your doctor in case it interacts with other prescribed medication.

COMBINED PILL
The combined contraceptive pill, containing both estrogen and progestin, is highly reliable. This is the most commonly used contraceptive among women under 35, who are in their most fertile period and need an effective method. There may be side effects, such as changes in weight and mood, but these usually disappear after the first few months of use.

The combined hormone pill lowers the risk of cancer of the ovary but increases the risk of some other disorders. Since the combined pill can cause a slight rise in blood pressure, you may be advised not to use it if you have a family history of high blood pressure (see Hypertension). It also causes blood to clot more readily, increasing your risk of stroke and heart attacks (see Myocardial infarction). The risk is substantially increased if you are over age 35 and smoke, but you should also avoid the combined pill if you are very overweight or have a family history of deep vein thrombosis.

PROGESTIN-ONLY PILL
This type of contraceptive pill contains only progestin and does not carry the health risks of the combined pill. It is effective but must be taken at the same time every day to be reliable. Taking the progestin pill often causes lighter menstrual periods but may also make your cycle irregular. However, its effect on menstruation does not alter its effectiveness as a contraceptive. There may be other side effects, such as acne and breast tenderness, but these should last only a few months. There is also a small risk of ovarian cysts or of having an ectopic pregnancy if you conceive while taking it.

INJECTIONS AND PATCHES
Injections of progestin or patches that deliver combined hormone treatment are reliable and give long-term protection. They are useful if you do not want children for several years or at all or if you regularly forget to take pills. However, they may initially make your menstrual periods irregular or heavier and may cause weight gain of about 2-4 lb (1-2kg). After the initial period, most women stop menstruating while the patches are in place or while they are receiving injections. Fertility may not return for several months after injections cease, but it returns quickly when use of the patch is stopped.

MECHANICAL METHODS

The intrauterine device (IUD) and intrauterine system (IUS) are contraceptive devices inserted into the uterus by a doctor. They cause changes in the uterus that prevent fertilized eggs from being implanted there. The IUS acts on the uterus in the same way as the IUD, but it also releases progestin. The devices provide immediate protection and last for several years. They may be difficult to insert if you have never been pregnant and may be better for women who wish to defer future pregnancies or have completed their families. Both the IUD and the IUS may increase your susceptibility to certain infections and may not be suitable if you have multiple short-term sexual contacts that increase your exposure to infections. There is a small risk that the IUD or IUS may be expelled from the uterus or pierce the uterus and enter the abdomen, causing a serious inflammation of the abdominal lining called peritonitis, which may be fatal.

The IUD does not affect hormones or ovulation, but it may worsen heavy or painful menstrual periods, especially in the first few months after insertion. The progestin in the IUS usually makes periods lighter and less painful after the first 3 months of use. The IUS can be useful for women with heavy menstrual periods or women nearing menopause because it greatly reduces blood loss during menstruation. There may be temporary side effects similar to those of the progestin-only pill.

NATURAL METHODS

Natural birth control involves working out when you are fertile and avoiding intercourse at those times. It does not affect the body and has no side effects. It can be used to determine when you can conceive, if you wish to. However, natural birth control can disrupt the spontaneity of sexual activity and should not be used without training. It also requires that you have a regular menstrual cycle. This method works best if you are in a long-term relationship and feel that you could handle an unplanned pregnancy.

SURGICAL METHODS

Surgical contraception, or sterilization, is an operation that makes you infertile. This surgery can be carried out on men or women. Since the operation is considered permanent, it is suitable only for those who are sure that they do not want children. The operations have low failure rates of about 1 in 1,000 men and 7 in 1,000 women.

Male sterilization (vasectomy) is not immediately effective. The seminal vesicles (sacs that hold semen) still contain sperm after the operation, and a condom must be used until semen analysis shows that no sperm are left. Female sterilization is effective immediately, but the risk of ectopic pregnancy is slightly increased.

EMERGENCY METHODS

Emergency contraception is used to prevent pregnancy if you have had unprotected sex or if you think that your contraception has not worked. If you have had sex within the previous 3 days, you may be given a hormone similar to an oral contraceptive (if the treatment will not pose health risks for you). An IUD may be inserted, depending on the dates of your unprotected sex and your last menstrual period.

HEALTH OPTIONS USING CONTRACEPTIVES
Contraception provides a high degree of protection against unwanted pregnancy, although the effectiveness of different methods varies. For each method described here, effectiveness is defined as the number of women per hundred per year who do not become pregnant while using it and is expressed as a percentage. For most methods, apart from the IUD or IUS, your doctor will need to explain how to use them so that they are effective. It may take some time to learn how to use a diaphragm, a cap, or natural methods, and they are not suitable for times when you need contraception immediately. A condom is usually the best method in this situation.

BARRIER METHODS

Condoms, diaphragms, and caps form barriers between the penis and the uterus to prevent sperm from reaching the egg. They may be used with spermicide, a substance that kills sperm. Barrier methods are 92-98 percent effective, and the male condom is the most effective. Most failures are due to incorrect use.

Cervical cap
The cap is partially filled with spermicide then pushed over the cervix. If intercourse does not occur within 3 hours of inserting it, extra spermicide must be added. To be effective, the cap must be left in place for at least 6 hours after intercourse.

Diaphragm
The diaphragm is coated with spermicide on both surfaces. It is positioned so that the concave side covers the cervix. Like the cervical cap, it must be left in place for at least 6 hours after intercourse.

Male condom
Before a condom is unrolled onto the penis, the air must be squeezed out of the reservoir (end) so that the condom will not split. After intercourse, the penis must be withdrawn with the condom held on to prevent semen from leaking out.

Female condom
The closed end of the condom is pushed up to the cervix. The open end extends just beyond the vaginal opening. During intercourse it is vital to make sure that the penis enters the condom, inside the vagina.

HORMONAL METHODS

Hormones are prescribed as pills, implants, or injections. Some hormonal contraceptives contain only progestin, which is a type of female hormone. Progestins act as a contraceptive by thickening the cervical mucus so that sperm cannot pass through; it also suppresses ovulation and changes the receptivity of the lining of the uterus. The combined pill contains progestin and estrogen and prevents ovulation. Hormonal methods are over 99 percent effective, but they must be taken at the same time each day.

Progestin-only pill
The progestin-only pill must be taken at approximately the same time each day, during every day in the menstrual cycle.

Combined oral contraceptive
The combined pill includes estrogen and progestin. The pills contain hormones for the first 21 days of each menstrual cycle. For the last 7 days, you take pills that contain no hormone or no pills at all. The pills must be taken in the specified order.

Contraceptive injection
Your doctor injects progestin into a muscle in your arm or buttock, and it is released into your body over 8 to 12 weeks. To maintain the protective effect, you must have the next injection before the supply of hormone from the first one runs out.

Patch
The patch contains estrogen and progestin that are released through the skin to prevent pregnancy. A new patch is placed on the skin once a week for three weeks; like combined oral contraceptives, no patch is needed the fourth week of each menstrual cycle.

MECHANICAL METHODS

The intrauterine device (IUD) and intrauterine system (IUS) are fitted by a doctor and can be left in place for 3-8 years. The IUD is thought to keep fertilized eggs from implanting in the uterus; some contain copper to kill sperm. The progestin in the IUS also thickens cervical mucus. Both are over 98 percent effective.

Intrauterine device (IUD)
An IUD has two threads that extend through the cervix. Once a month, the user should check that the threads are still there to make sure that the IUD has not been expelled during menstruation.

NATURAL METHODS
Natural methods of contraception are used to identify days in your menstrual cycle when you are fertile and times when you are less likely to conceive. Having identified these times, you can refrain from sex on your fertile days or use another form of contraception. The symptothermal method, which is only about 80 percent effective, is the most commonly used natural method. It is based on two factors: body temperature rising just after ovulation (which occurs 12-16 days before each period) and staying high for at least 3 days and increased amounts of mucus in the vagina around the time of ovulation. If you plan to use natural methods, seek advice from your doctor first.

Using a temperature chart
You can monitor your fertility by recording your temperature on a chart like the one shown here. Take your temperature at the same time every day, immediately after waking and before getting up. Ovulation (on day 15 on this chart) is followed by a rise in temperature. When you have recorded higher temperatures for 3 days in a row, your fertile time is over. A period of infertility then follows and continues until the last day of your next menstrual period.

By David R. Goldmann, EDITOR-IN-CHIEF and David A. Horowitz, ASSOCIATE EDITOR

David R. Goldmann, MD, FACP is Vice President and Editor-in-Chief of the Physician’s Information and Education Resource at the American College of Physicians, Associate Editor of the Annals of Internal Medicine, and Associate Editor of the Annals of Internal Medicine, and Associate Professor of Medicine at the Hospital of the University of Pennsylvania.

David A. Horowitz, MD is Medical Director of the Department of Clinical Effectiveness and Quality Improvement, University of Pennsylvania Health System, and Assistant Professor of Medicine at the Hospital of the University of Pennsylvania.

Complete Home Medical Guide (Print version published in association with the American College of Physicians); 2003, p67-71, 5p, 2 diagrams, 1 graph, 13c