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What is chlamydia?

Chlamydia (say "kluh-MID-ee-uh") is an infection spread through sexual contact. This infection infects the urethra in men. In women, it infects the urethra and the cervix and can spread to the reproductive organsClick here to see an illustration.. It is one of the most common sexually transmitted infections (STIs).

Chlamydia does not cause problems if you treat it right away. But left untreated, it can lead to serious problems, especially for women:

  • If it spreads, it can cause pelvic inflammatory disease. This serious infection can make it hard or impossible for a woman to get pregnant.
  • Pregnant women who have chlamydia often pass it to their babies at birth. If the infection gets in a baby's eyes, it can cause blindness. They can also have other problems, like pneumonia. Pneumonia can be deadly in a newborn.
  • Having chlamydia makes a person more likely to get HIV from someone who is infected with HIV. HIV is the virus that causes AIDS.

What causes chlamydia?

A certain kind of bacteria causes chlamydia. It can spread from one partner to another through vaginal, anal, or oral sex. A pregnant woman can pass the infection to her newborn during delivery.

What are the symptoms?

Most people don't have symptoms. When symptoms do occur, they can include pain when you urinate, cloudy urine, or an abnormal discharge from the penis or vagina.

You can spread chlamydia even if you do not have symptoms. You are contagious until you have been treated.

How is chlamydia diagnosed?

Your doctor will ask you questions about your past health and your sexual history, such as how many partners you have. You may also have a physical exam to look for signs of infection.

Several types of tests can be used to diagnose chlamydia. Most use a sample of urine or a swab from the cervix, vagina, or urethra.

Since chlamydia can cause serious problems but may not cause symptoms, it's a good idea to get tested once a year if you are sexually active and in your mid-20s or younger. Local health departments and family planning clinics usually offer low-cost testing.

How is it treated?

Antibiotics are used to treat chlamydia. It's important to take all of the medicine as directed. Otherwise the medicine may not work. Both sex partners need treatment to keep from passing the infection back and forth.

As soon as you find out you have chlamydia, be sure to let your sex partners know. Experts recommend that you notify everyone you've had sex with in the past 2 months. If you have not had sex in the past 2 months, contact the last person you had sex with.


Some people who have chlamydia also have other STIs, such as gonorrhea.


How can I prevent chlamydia?

It's easier to prevent an STI like chlamydia than it is to treat it:

  • 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 infections that all of their partners may have.

Frequently Asked Questions

Learning about chlamydia:

Being diagnosed:

Getting treatment:

Ongoing concerns:

Living with chlamydia:


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