STIs are also called sexually transmitted diseases (STDs).
These infections are spread by direct contact with a sore on the genitals or mouth, body fluids, or sometimes the skin around the genital area.
Before having sex:
Get to know your partner and discuss your sexual histories
Don't feel forced into having sex
Don't have sexual contact with anyone but your partner
Your sexual partner should be someone who you know does not have any STI. Before having sex with a new partner, each of you should get screened for STIs and share the test results with each other.
If you know you have an STI such as HIV or herpes, let any sexual partner know this before you have sex. Allow him or her to decide what to do. If you both agree to have sexual contact, use latex or polyurethane condoms.
Use condoms for all vaginal, anal, and oral intercourse.
The condom should be in place from the beginning to the end of the sexual activity. Use it every time you have sex.
Keep in mind that STIs can be spread by contact with skin areas around the genitals. A condom reduces but does not eliminate your risk of getting an STI.
Other tips include:
Use lubricants. They may help reduce the chance that a condom will break.
Use only water-based lubricants. Oil-based or petroleum-type lubricants can cause latex to weaken and tear.
Polyurethane condoms are less likely to break than latex condoms, but they cost more.
Using condoms with nonoxynol-9 (a spermicide) may increase the chance of HIV transmission.
Stay sober. Alcohol and drugs impair your judgment. When you are not sober, you might not choose your partner as carefully. You may also forget to use condoms, or use them incorrectly.
Get tested regularly for STIs if you have new sexual partners. Most STIs have no symptoms, so you need to be tested often if there is any chance you have been exposed. You will have the best outcome and will be less likely to spread the infection if you are diagnosed early.
Women should consider getting the HPV vaccine to keep from getting the human papillomavirus. This virus can put you at risk for vaginal warts and cervical cancer.
Eckert LO, Lentz GM. Infections of the lower genital tract: vulva, vagina, cervix, toxic shock syndrome, endometritis, and salpingitis. In: Lentz GM, Lobo RA, Gershenson DM, Katz VL, eds. Comprehensive Gynecology. 6th ed. Philadelphia, PA: Elsevier Mosby; 2012: chap 23.
Lin JS, Whitlock E, O'Connor E, Bauer V. Behavioral counseling to prevent sexually transmitted infections: A Systematic Review for the U.S. Preventive Services Task Force. Ann Intern Med. 2008;149:497-508.
Markle W, Conti T, Kad M. Sexually transmitted diseases. Prim Care Clin Office Pract. 2013;40:557-587.
Cynthia D. White, MD, Fellow American College of Obstetricians and Gynecologists, Group Health Cooperative, Bellevue, WA. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.