Chlamydia is a common sexually transmitted infection (STI). It is caused by bacteria called Chlamydia trachomatis. Anyone can get chlamydia. It often doesn't cause symptoms, so people may not know that they have it. Antibiotics can cure it. But if it's not treated, chlamydia can cause serious health problems.

You can get chlamydia during oral, vaginal, or anal sex with someone who has chlamydia. A pregnant person can also pass chlamydia to the baby during childbirth.

If you've had chlamydia and were treated in the past, you can get re-infected if you have unprotected sex with someone who has it.

Chlamydia is more common in young people, especially young women. You are more likely to get infected with chlamydia if you don't consistently use a condom or if you have multiple partners.

Chlamydia doesn't usually cause any symptoms. So you may not realize that you have it. But even if you don't have symptoms, you can still pass the infection to others.

If you do have symptoms, they may not appear until several weeks after you have sex with someone who has chlamydia.

Symptoms in women include:

• Abnormal vaginal discharge, which may have a strong smell
• A burning sensation when urinating

If the infection spreads, you might get lower abdominal (belly) pain, pain during sex, nausea, and fever.

Symptoms in men include:

• Discharge from your penis
• A burning sensation when urinating (peeing)
• Pain and swelling in one or both testicles (although this is less common)

If the chlamydia infects the rectum (in men or women), it can cause rectal pain, discharge, and bleeding.

There are lab tests to diagnose chlamydia. Your health care provider may ask you to provide a urine sample. Or your provider may use (or ask you to use) a cotton swab to get a sample from your vagina to test for chlamydia.

You should go to your provider for a test if you have symptoms of chlamydia or if you have a partner who has an STI. Pregnant people should get a test when they go to their first prenatal visit.

People at higher risk should get checked for chlamydia every year:

• Sexually active women 25 and younger
• Older women who have new or multiple sex partners or a sex partner who has an STI
• Men who have sex with men (MSM)

In women, an untreated infection can spread to your uterus and fallopian tubes, causing pelvic inflammatory disease (PID). PID can cause permanent damage to your reproductive system. This can lead to long-term pelvic pain, infertility, and ectopic pregnancy. Women who have had chlamydia infections more than once are at higher risk of serious reproductive health complications.

Men often don't have health problems from chlamydia. Sometimes it can infect the epididymis (the tube that carries sperm). This can cause pain, fever, and, rarely, infertility.

Both men and women can develop reactive arthritis because of a chlamydia infection. Reactive arthritis is a type of arthritis that happens as a "reaction" to an infection in the body.

Babies born to infected mothers can get eye infections and pneumonia from chlamydia. It may also make it more likely for your baby to be born too early.

Untreated chlamydia may also increase your chances of getting or giving HIV.

Antibiotics will cure the infection. You may get a one-time dose of the antibiotics, or you may need to take medicine every day for 7 days. It is important to take all the medicine that your provider prescribed for you. Antibiotics cannot repair any permanent damage that the disease has caused.

To prevent spreading the disease to your partner, you should not have sex until the infection has cleared up. If you got a one-time dose of antibiotics, you should wait 7 days after taking the medicine to have sex again. If you have to take medicine every day for 7 days, you should not have sex again until you have finished taking all of the doses of your medicine.

It is common to get a repeat infection, so you need to get tested again about three months after treatment.

The only sure way to prevent chlamydia is to not have vaginal, anal, or oral sex.

Correct usage of latex condoms greatly reduces, but does not eliminate, the risk of catching or spreading chlamydia. If your or your partner is allergic to latex, you can use polyurethane condoms.

Centers for Disease Control and Prevention