Sexually transmitted infections (STIs) are spread by sexual contact involving the genitals, mouth, or rectum, and can also be spread from a pregnant woman to her fetus before or during delivery. STIs, which affect both men and women, are a worldwide public health concern.
STIs can be spread by people who don't know they are infected. Always use protection every time you have sex, including oral sex, until you are sure you and your partner are not infected with an STI.
If you are in a relationship, delay having sex until you are physically and emotionally prepared, have agreed to only have sex with each other, and have both been tested for STIs.
Abstinence as prevention
Completely avoiding sexual contact (abstinence), including intercourse and oral sex, is the only certain way to prevent an infection.
Discuss safer sex with your partner
Discuss STIs before you have sex with someone. Even though a sex partner doesn't have symptoms of an STI, he or she may still be infected.
Questions to ask someone before having sex include:
- How many people have you had sex with?
- Have you had sex without a condom?
- Have you ever had unprotected oral sex?
- Have you had more than one sex partner at a time?
- Do you inject illegal drugs or have you had sex with someone who injects drugs?
- Have you ever had unprotected sex with a prostitute?
- Have you had a test for HIV? What were the results?
- Have you ever had an STI, including hepatitis B or hepatitis C? Was it treated and cured?
Safer sex practices
Some STIs, such as HIV, can take up to 6 months before they can be detected in the blood. Genital herpes and the human papillomavirus (HPV) can be spread when symptoms are not present. Even if you and your partner have been tested, use condoms for all sex until you and your partner haven't had sex with another person for 6 months. Then get tested again.
- Watch for symptoms of STIs, such as unusual discharge, sores, redness, or growths in your and your partner's genital area, or pain while urinating.
- Don't have more than one sex partner at a time. The safest sex is with one partner who has sex only with you. Every time you add a new sex partner, you are being exposed to all of the diseases that all of their partners may have. Your risk for an STI increases if you have several sex partners at the same time.
- Use a condom every time you have sex. A condom is the best way to protect yourself from STIs. Latex and polyurethane condoms do not let STI viruses pass through, so they offer good protection from STIs. Condoms made from sheep intestines do not protect against STIs.
- Use a water-based lubricant such as K-Y Jelly or Astroglide to help prevent tearing of the skin if there is a lack of lubrication during sexual intercourse. Small tears in the vagina during vaginal sex or in the rectum during anal sex allow STI bacteria or viruses to get into your blood.
- Avoid douching if you are a woman, because it can change the normal balance of organisms in the vagina and increases the risk of getting an STI.
- A mouth barrier, such as a dental dam, can be used to reduce the spread of infection through oral sexual activity. You can discuss this method with your dentist or doctor.
- Tell your sex partner or partners if you have symptoms of an infection or if you're being treated for an STI, such as HIV or herpes. If you or your partner has herpes, avoid sexual contact when a blister is present. If you and your partner have sex, use a latex condom.
For more information see: Sexually Transmitted Infections.
Current as of: November 17, 2021
Author: Healthwise Staff
Medical Review: E. Gregory Thompson MD - Internal Medicine
Adam Husney MD - Family Medicine
Peter Shalit MD, PhD - Internal Medicine