Topic Overview

Sexually transmitted infections (STIs) are some of the most widespread infections both in the United States and the world. STIs affect both men and women, and two-thirds of all STIs occur in people younger than 25. Exposure to an STI can occur any time you have sexual contact that involves the genitals, the mouth (oral), or the rectum (anal). Exposure is more likely if you have more than one sex partner or do not use condoms. Some STIs can be spread by nonsexual contact, such as during the delivery of a baby or during breastfeeding.

It is important to practice safer sex with all partners, especially if you or they have high-risk sexual behaviors.

There are at least 20 different STIs. Testing recommendations for some of the most common STIs in the U.S. follow. In general, testing is recommended for those at high risk.

Chlamydia

Chlamydia is a common STI in the United States. Left untreated, chlamydia can lead to many complications, especially for women. If a woman has chlamydia when she gives birth, her newborn can have the infection.

The U.S. Preventive Services Task Force (USPSTF) recommends chlamydia testing for all sexually active women ages 24 and younger. The USPSTF also recommends testing for women older than 24 with high-risk sexual behaviors. The task force does not state how often to be screened. After reviewing all of the research, the USPSTF has not recommended for or against regular chlamydia screening for men.^{footnote 2}

The Centers for Disease Control and Prevention (CDC) recommends screening every year for sexually active adolescents and women ages 24 and younger. Women older than 24 who have high-risk sexual behaviors also should be screened every year.^{footnote 3} You may have a urine test for chlamydia (if it is available in your area) even if you do not have a full pelvic or genital exam.

The CDC recommends tests for pregnant women with high-risk sexual behaviors so they do not spread chlamydia to their babies. All pregnant women should be screened during their first prenatal visit. If a pregnant woman is at high risk for chlamydia, she may be tested again during her third trimester.

The CDC also recommends you have the test again 3 to 12 months after you finish treatment. Women who have been diagnosed and treated for chlamydia may get it again if they have sex with the same partner or partners.^{footnote 3}

For more information, see the topic Chlamydia.

Syphilis

The U.S. Centers for Disease Control and Prevention (CDC) and the U.S. Preventive Services Task Force (USPSTF) strongly recommend that all pregnant women be screened for syphilis because of the severe consequences of being pregnant while infected or having a child born with congenital syphilis.^{footnote 1} Screening should be done:^{footnote 3}

• At the first prenatal visit for all pregnant women.
• During the third trimester and again at delivery for pregnant women who have an increased risk of acquiring syphilis.^{footnote 3}

The USPSTF also strongly recommends that anyone with high-risk sexual behaviors be screened.

Yearly testing for syphilis is recommended for men who are sexually active with other men. If these men also engage in risky sexual behavior, have HIV, or have a sex partner with syphilis, testing should take place more often.

For more information, see the topic Syphilis.

Gonorrhea

The USPSTF recommends testing all sexually active women ages 24 and younger. The USPSTF also recommends testing for women older than 24 who engage in high-risk sexual behaviors.^{footnote 2}

If you engage in high-risk sexual behaviors, you may want to consider being tested once a year for gonorrhea even though you don’t have symptoms. Testing will allow gonorrhea to be quickly diagnosed and treated. This helps to reduce the risk of transmitting gonorrhea and avoid complications of the infection.

The Centers for Disease Control and Prevention (CDC) also recommends testing for pregnant women who engage in high-risk sexual behaviors to prevent them from transmitting gonorrhea to their babies. All pregnant women should be tested during their first prenatal visit. If a pregnant woman is at high risk for gonorrhea, she may be tested again during the third trimester before delivery to prevent transmitting the infection to her newborn.^{footnote 3}

For more information, see the topic Gonorrhea.

Other types of STIs include:

• Genital warts or human papillomavirus (HPV). Certain types of HPV can cause cancer of the cervix.
• Genital herpes.
• Hepatitis B.
• Trichomoniasis.

Other infections that may be sexually transmitted include human immunodeficiency virus (HIV), hepatitis A, cytomegalovirus, scabies, pubic lice, molluscum contagiosum, hepatitis C, and possibly bacterial vaginosis.

For more information, see the topic Sexually Transmitted Infections.