Medically Reviewed By William C. Lloyd III, MD, FACS

What is chlamydia?

Chlamydia is a sexually transmitted disease (STD). It is the most common bacterial STD in the United States, according to the Centers for Disease Control and Prevention (CDC). The bacterium, Chlamydia trachomatis, causes the infection.

Any person who engages in sexual activity can contract and pass on a chlamydia infection. This includes heterosexual, homosexual, and bisexual men and women. The more sexual partners a person has, the greater the risk of catching chlamydia. Girls and young women have an especially high risk of getting the infection. An infected mother can pass chlamydia to her newborn during vaginal delivery. This can create serious medical complications for the newborn.

Chlamydia is preventable and treatable. Doctors diagnose it by testing a small sample of cells or discharge taken from a woman’s cervix or a man’s urethra. Chlamydia treatment involves antibiotic therapy. Sexual partners of infected people should be tested and treated.

Although there are often no symptoms or only mild symptoms, untreated chlamydia infection can lead to serious complications. This includes pelvic inflammatory disease and infertility. Practicing safe sex and seeking regular medical care, including prenatal care, can help reduce the risk of serious complications from the infection.

What are the symptoms of chlamydia?

Chlamydia symptoms vary. Some people have no symptoms at all, especially in the early stages of the disease. Women are particularly likely to not have early symptoms. However, serious permanent damage to the reproductive tissues and infertility can occur even in the absence of symptoms. When symptoms do appear, they generally occur 1 to 3 weeks after exposure.

Symptoms of chlamydia in women include:

  • Lower abdominal pain

  • Pain or burning with urination

  • Painful sexual intercourse

  • Unusual vaginal discharge

Symptoms of chlamydia in men include:

Symptoms that might indicate a serious or life-threatening condition

In some cases, advanced chlamydia infection can lead to serious, even life-threatening conditions. This includes pelvic inflammatory disease and pelvic abscess. Seek immediate medical care for potentially serious symptoms including:

Chlamydia infection can also be passed from an infected mother to her baby during vaginal delivery. This can lead to eye infection, blindness, and pneumonia in the newborn. If you are experiencing symptoms or you are concerned about chlamydia, it’s important to contact a healthcare provider.

What causes chlamydia?

A bacterial infection of the genitals (and cervix in women) causes chlamydia. The bacterium, Chlamydia trachomatis, is responsible for the infection. The infection passes from one person to another during sexual contact that involves vaginal, oral or anal sex. An infected mother can also pass the infection to her baby during vaginal delivery.

What are the risk factors for chlamydia?

Any person who engages in sexual activity can get chlamydia. However, there are a number of factors that increase the risk of contracting the infection. Risk factors for chlamydia include:

  • Being a girl or young woman because their reproductive organs are not fully mature and are more susceptible to infection

  • Being born via vaginal delivery to a mother with chlamydia

  • Having multiple sexual partners

  • Having unprotected sex, including vaginal, oral or anal sex, with a partner who has had one or more other sexual partners

How do you prevent chlamydia?

Catching and passing on a chlamydia infection is preventable. It is important to understand that it is possible to transmit chlamydia even when there are no symptoms. You may be able to lower your risk of contracting and spreading chlamydia by:

  • Abstaining from sexual activity after being diagnosed with chlamydia until you and your sexual partner(s) have been completely treated and cleared by a health care provider to resume sexual activity 

  • Engaging in sexual activities only within a mutually monogamous relationship in which neither partner is infected with chlamydia or has risk factors for chlamydia

  • Using a new latex condom properly for each sex act

  • Getting regular, routine medical care

  • Seeking medical care as soon as possible after possible exposure to chlamydia or after high-risk sexual activity

  • Seeking prenatal care early and regularly during a pregnancy, which also includes screenings for chlamydia.

Current guidelines recommend annual chlamydia screening for sexually active women 25 years of age and younger—the highest risk group. Annual screening is also wise for other men and women at high risk, such those with multiple partners or men who have sex with men. Pregnant women should have a screening at their first prenatal visit. You should repeat the screening if you change sexual partners or have a new sexual partner before your annual screening is due.

How do doctors diagnose chlamydia?

To diagnose chlamydia, your doctor will take a medical history, perform an exam, and order testing. Questions your doctor may ask about your symptoms and sexual history include:

  • Are you sexually active?

  • Do you have a new sexual partner?

  • How many sexual partners do you have?

  • What symptoms are you having, such as unusual discharge?

  • Are you experiencing pelvic pain or pain with urination?

  • For women, when was your last menstrual period?

If you are a woman, the physical exam will likely include a pelvic exam. During the pelvic exam, your doctor will take a sample of vaginal fluid. For the screening exam, the doctor can collect a sample from the cervix during a Pap test. In some cases, women may collect a vaginal fluid sample themselves if a doctor recommends a home testing kit.

If you are a man, it is possible that a doctor may need to collect a sample from your urethra. However, it is more common to do a first-catch or clean-catch urine collection for testing. Sometimes, doctors use a urine test for women too, to determine if the infection has spread to the urinary tract.

Additional STD screening may be necessary depending on your risks. For women, additional testing may include a pregnancy test.

How do you treat chlamydia?

Chlamydia is a treatable STD. Prompt diagnosis and treatment can reduce the risk of developing serious complications and minimize the spread of the disease to others. You can cure chlamydia by consistently following your treatment plan. Treatment plans generally include antibiotic medications and other treatments.

Antibiotic medications for chlamydia include:

Other treatments for chlamydia include:

  • Abstaining from sexual activity until the infection is completely gone and all recent sexual partners have been contacted and treated, even if they have no symptoms. This generally means no sex for seven days.

  • Hospitalization or surgery for complications, such as pelvic inflammatory disease and pelvic abscess

What are the potential complications of chlamydia?

Complications of untreated chlamydia can be serious. You can minimize the risk of serious complications by following your treatment plan.

Serious complications of chlamydia include:

  • An increased risk of contracting HIV

  • Ectopic pregnancy

  • Epididymitis

  • Infertility

  • Pelvic abscess

  • Pelvic inflammatory disease

  • Reiter’s syndrome

  • Prostatitis

  • Scarring of the fallopian tubes and infertility

Serious complications of prenatal chlamydia

Newborn babies are at risk if their mothers have chlamydia during pregnancy and delivery. Chlamydia infection can be passed from an infected mother to her baby during vaginal delivery and lead to serious complications including:

  • Loss of vision and blindness

  • Newborn pneumonia

  • Premature delivery

If you are pregnant and experiencing symptoms or you are concerned about chlamydia, contact your healthcare provider.

Was this helpful?
  1. Chlamydia. Cleveland Clinic. 
  2. Chlamydia Fact Sheet. Centers for Disease Control and Prevention. 
  3. Chlamydia Test. MedlinePlus, National Library of Medicine, National Institutes of Health. 
  4. Chlamydia Testing. Lab Tests Online. 
  5. Chlamydia Trachomatis. Mayo Foundation for Medical Education and Research. 
  6. Mohseni M, Sung S, Takov V. Chlamydia. [Updated 2021 Aug 11]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2021 Jan-. Available from: 
  7. Tierney LM Jr., Saint S, Whooley MA (Eds.) Current Essentials of Medicine (4th ed.). New York: McGraw-Hill, 2011.

Medical Reviewer: William C. Lloyd III, MD, FACS
Last Review Date: 2021 Oct 4
View All Sexual Health Articles
THIS TOOL DOES NOT PROVIDE MEDICAL ADVICE. It is intended for informational purposes only. It is not a substitute for professional medical advice, diagnosis or treatment. Never ignore professional medical advice in seeking treatment because of something you have read on the site. If you think you may have a medical emergency, immediately call your doctor or dial 911.