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Chlamydia fact sheet

What is chlamydia and how common is it?

Chlamydia (kluh-MID-ee-uh) is a sexually transmitted infection (STI). STIs are also called STDs, or sexually transmitted diseases. Chlamydia is an STI caused by bacteria called chlamydia trachomatis. Chlamydia is the most commonly reported STI in the United States. Women, especially young women, are hit hardest by chlamydia.

Women often get chlamydia more than once, meaning they are "reinfected." This can happen if their sex partners were not treated. Reinfections place women at higher risk for serious reproductive health problems, such as infertility.

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How do you get chlamydia?

You get chlamydia from vaginal, anal, or oral sex with an infected person. Chlamydia often has no symptoms. So people who are infected may pass chlamydia to their sex partners without knowing it. The more sex partners you (or your partner) have, the higher your risk of getting this STI.

An infected mother can pass chlamydia to her baby during childbirth. Babies born to infected mothers can get pneumonia (nuh-MOHN-yuh) or infections in their eyes.

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What are the symptoms of chlamydia?

Chlamydia is known as a "silent" disease. This is because 75 percent of infected women and at least half of infected men have no symptoms.

If symptoms do occur, they most often appear within 1 to 3 weeks of exposure. The infection first attacks the cervix and urethra. Even if the infection spreads to the uterus and fallopian tubes, some women still have no symptoms. If you do have symptoms, you may have:

  • Abnormal vaginal discharge
  • Burning when passing urine
  • Lower abdominal pain
  • Low back pain
  • Nausea
  • Fever
  • Pain during sex
  • Bleeding between periods

Men with chlamydia may have:

  • Discharge from the penis
  • Burning when passing urine
  • Burning and itching around the opening of the penis
  • Pain and swelling in the testicles

The chlamydia bacteria also can infect your throat if you have oral sex with an infected partner.

Chlamydia is often not diagnosed or treated until problems show up. If you think you may have chlamydia, both you and your sex partner(s) should see a doctor right away — even if you have no symptoms.

Chlamydia can be confused with gonorrhea (gahn-uh-REE-uh), another STI. These STIs have some of the same symptoms and problems if not treated. But they have different treatments.

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How is chlamydia diagnosed?

A doctor can diagnose chlamydia through:

  • A swab test, where a fluid sample from an infected site (cervix or penis) is tested for the bacteria
  • A urine test, where a urine sample is tested for the bacteria
A Pap test is not used to detect chlamydia.

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Who should get tested for chlamydia?

You should be tested for chlamydia once a year if you are:

  • 25 or younger and have sex
  • Older than 25 and:
    • Have a new sex partner
    • Have more than one sex partner
    • Have sex with someone who has other sex partners
    • Have had chlamydia or another STI in the past
    • Have traded sex for money or drugs
    • Do not use condoms during sex within a relationship that is not mutually monogamous, meaning you or your partner has sex with other people
  • Pregnant
You also should be tested if you have any symptoms of chlamydia.

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What is the treatment for chlamydia?

Antibiotics are used to treat chlamydia. If treated, chlamydia can be cured.

All sex partners should be treated to keep from getting chlamydia again. Do not have sex until you and your sex partner(s) have ended treatment.

Tell your doctor if you are pregnant! Your doctor can give you an antibiotic that is commonly used during pregnancy.

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What should I do if I have chlamydia?

Chlamydia is easy to treat. But you should be tested and treated right away to protect your reproductive health. If you have chlamydia:

  • See a doctor right away. Women with chlamydia are 5 times more likely to get HIV, the virus that causes AIDS, from an infected partner.
  • Follow your doctor's orders and finish all your antibiotics. Even if symptoms go away, you need to finish all the medicine.
  • Don't engage in any sexual activity while being treated for chlamydia.
  • Tell your sex partner(s) so they can be treated.
  • See your doctor again if your symptoms don't go away within 1 to 2 weeks after finishing the medicine.
  • See your doctor again within 3 to 4 months for another chlamydia test. This is most important if your sex partner was not treated or if you have a new sex partner.

Doctors, local health departments, and STI and family planning clinics have information about STIs. And they can all test you for chlamydia. Don't assume your doctor will test you for chlamydia when you have your Pap test. Take care of yourself by asking for a chlamydia test.

The Centers for Disease Control and Prevention (CDC) has free information and offers a list of clinics and doctors who provide treatment for STIs. Call CDC-INFO at 800-CDC-INFO (232-4636), TTY: 888-232-6348. You can call for information without leaving your name.

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What health problems can result from untreated chlamydia?

Untreated chlamydia can damage a woman's reproductive organs and cause other health problems. Like the disease itself, the damage chlamydia causes is often "silent."

For women, untreated chlamydia may lead to:
  • Pelvic inflammatory disease (PID). PID occurs when chlamydia bacteria infect the cells of the cervix, then spread to the uterus, fallopian tubes, and ovaries. PID occurs in up to 40 percent of women with untreated chlamydia. PID can lead to:
    • Infertility, meaning you can't get pregnant. The infection scars the fallopian tubes and keeps eggs from being fertilized.
    • Ectopic or tubal pregnancy. This happens when a fertilized egg implants outside the uterus. It is a medical emergency.
    • Chronic pelvic pain, which is ongoing pain, most often from scar tissue.
  • Cystitis (siss-TEYE-tuhss), inflammation of the bladder.
  • HIV/AIDS. Women who have chlamydia are 5 times more likely to get HIV, the virus that causes AIDS, from a partner who is infected with it.

For men, untreated chlamydia may lead to:

  • Infection and scarring of the urethra, the tube that carries urine from the body
  • Prostatitis (prah-stuh-TEYE-tuhss), swelling of the prostate gland
  • Infection in the tube that carries sperm from the testes, causing pain and fever
  • Infertility

For women and men, untreated chlamydia may lead to:

  • Chlamydia bacteria in the throat, if you have oral sex with an infected partner
  • Proctitis (prok-TEYE-tuhss), which is an infection of the lining of the rectum, if you have anal sex with an infected partner
  • Reiter's syndrome, which causes arthritis, eye redness, and urinary tract problems

For pregnant women, chlamydia infections may lead to premature delivery. And babies born to infected mothers can get:

  • Infections in their eyes, called conjunctivitis (kuhn-junk-tih-VEYE-tuhss) or pinkeye. Symptoms include discharge from the eyes and swollen eyelids. The symptoms most often show up within the first 10 days of life. If left untreated, it can lead to blindness.
  • Pneumonia. Symptoms include congestion and a cough that keeps getting worse. Both symptoms most often show up within 3 to 6 weeks of birth.
Both of these infant health problems can be treated with antibiotics.

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How can chlamydia be prevented?

You can take steps to lower your risk of getting chlamydia and other STIs. The following steps work best when used together. No single strategy can protect you from every type of STI.

  • Don't have sex. The surest way to avoid getting chlamydia or any STI is to practice abstinence. This means not having vaginal, anal, or oral sex.
  • Be faithful. Having sex with only one unaffected partner who only has sex with you will keep you safe from chlamydia and other STIs. Both parthers must be faithful all the time to avoid STI exposure. This means you have sex only with each other and no one else. The fewer sex partners you have, the lower your risk of being exposed to chlamydia and other STIs.
  • Use condoms correctly and every time you have sex. Use condoms for all types of sexual contact, even if pen­etration does not take place. Condoms work by keeping blood, a man's semen, and a woman's vaginal fluid — all of which can carry chlamydia — from pass­ing from one person to another. Use protection from the very beginning to the very end of each sex act, and with every sex partner. And be prepared: Don't rely on your partner to have protection.
  • Know that most methods of birth control — and other methods — will not protect you from chlamydia and other STIs. Birth control methods including the pill, shots, implants, intrauterine devices (IUDs), diaphragms, and spermicides will not protect you from STIs. If you use one of these birth control methods, make sure to also use a condom with every sex act. You might have heard of other ways to keep from getting STIs — such as washing genitals before sex, passing urine after sex, douching after sex, or washing the genital area with vinegar after sex. These methods do not prevent the spread of STIs.
  • Talk with your sex partner(s) about STIs and using condoms before having sex. Make it clear that you will not have any type of sex at any time without a condom. It's up to you to make sure you are protected. Remember, it's your body! For more information, call the CDC at 800-232-4636.
  • Get tested for STIs. If either you or your partner has had other sexual part­ners in the past, get tested for STIs before becoming sexually active. This includes women who have sex with women. Most women who have sex with women have had sex with men, too. So a woman can get an STI, including chlamydia, from a male partner, and then pass it to a female partner. Don't wait for your doctor to ask you about getting tested — ask your doctor! Many tests for STIs can be done at the same time as your regular pelvic exam.
  • Learn the symptoms of chlamydia. But remember, chlamydia often has no symptoms. Seek medical help right away if you think you may have chlamydia or another STI.
  • Have regular checkups and pelvic exams — even if you think you're healthy. During the checkup, your doctor will ask you a lot of questions about your lifestyle, including your sex life. This might seem too personal to share. But answering honestly is the only way your doctor is sure to give you the care you need.

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More information on chlamydia

For more information about chlamydia, call womenshealth.gov at 800-994-9662 (TDD: 888-220-5446) or contact the following organizations:

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Content last updated July 08, 2011.

Resources last updated March 20, 2009.

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