Safe sex means taking precautions during sex that can keep you from getting a sexually transmitted disease (STD), or from giving an STD to your partner. These diseases include genital herpes, genital warts, HIV, Chlamydia, gonorrhea, syphilis, hepatitis B and C, and others.

A STD is a contagious disease that can be transferred to another person through sexual intercourse or other sexual contact. Many of the organisms that cause sexually-transmitted diseases live on the penis, vagina, anus, mouth, and the skin of surrounding areas.

Most of the diseases are transferred by direct contact with a sore on the genitals or mouth. However, some organisms can be transferred in body fluids without causing a visible sore. They can be transferred to another person during oral, vaginal, or anal intercourse.

Some STDs can also be transferred by nonsexual contact with infected tissues or fluids, such as infected blood. For example, sharing needles when using IV drugs is a major cause of HIV and hepatitis B transmission. An STD can also be transmitted through contaminated blood transfusions and blood products, through the placenta from the mother to the fetus, and sometimes through breast feeding.

The following factors increase your risk of getting a sexually-transmitted disease (STD):

• Not knowing whether a partner has an STD or not
• Having a partner with a past history of any STD
• Having sex without a male or female condom
• Using drugs or alcohol in a situation where sex might occur
• If your partner is an IV drug user
• Having anal intercourse

Drinking alcohol or using drugs increase the likelihood that you will participate in high-risk sex. In addition, some diseases can be transferred through the sharing of used needles or other drug paraphernalia.

Abstinence is an absolute answer to preventing STDs. However, abstinence is not always a practical or desirable option.

Next to abstinence, the least risky approach is to have a monogamous sexual relationship with someone that you know is free of any STD. Ideally, before having sex with a new partner, each of you should get screened for STDs, especially HIV and hepatitis B, and share the test results with one another.

Use condoms to avoid contact with semen, vaginal fluids, or blood. Both male and female condoms dramatically reduce the chance you will get or spread an STD. However, condoms must be used properly:

• The condom should be in place from the beginning to end of sexual activity and should be used every time you have sex.
• Lubricants may help reduce the chance a condom will break. Use only water-based lubricants, because oil-based or petroleum-type lubricants can cause latex to weaken and tear. Do NOT use condoms with nonoxynol-9 -- these help prevent pregnancy, but may increase the chance of HIV transmission.
• Use latex condoms for vaginal, anal, and oral intercourse.
• Keep in mind that STDs can still be spread, even if you use a condom, because a condom does not cover surrounding skin areas. But a condom definitely reduces your risk.

Here are additional safe-sex steps:

• Know your partner. Before having sex, first establish a committed relationship that allows trust and open communication. You should be able to discuss past sexual histories, any previous STDs or IV drug use. You should not feel coerced or forced into having sex.
• Stay sober. Alcohol and drugs impair your judgment, communication abilities, and ability to properly use condoms or lubricants.
• Be responsible. If you have an STD, like HIV or herpes, advise any prospective sexual partner. Allow him or her to decide what to do. If you mutually agree on engaging in sexual activity, use latex condoms and other measures to protect the partner.
• If pregnant, take precautions. If you have an STD, learn about the risk to the infant before becoming pregnant. Ask your provider how to prevent the fetus from becoming infected. HIV positive women should not breastfeed their infant.

In summary, safe sex requires prior planning and good communication between partners. Given that, couples can enjoy the pleasures of a sexual relationship while reducing the potential risks involved.

For information about preventing pregnancy, see birth control and family planning.

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Cohn SE. Sexually transmitted diseases, HIV, and AIDS in women. Med Clin North Am. 2003; 87(5): 971-995.

Greydanus DE. Contraception for college students. Pediatr Clin North Am. 2005; 52(1): 135-161, ix.