Chlamydia in Women

Chlamydia in Women

Reviewed By:
Marc Kaufman, M.D., ACOG
David Lubetkin, M.D., FACOG
Joanne Poje Tomasulo, M.D., ACOG


Chlamydia is a common sexually transmitted disease (STD) caused by a bacterium called Chlamydia trachomatis. If left untreated, it can cause numerous medical problems, including serious damage to a woman’s reproductive organs.

Both women and men are affected, although there are far more reported cases of chlamydia in women than men. It is transmitted through vaginal, anal and oral sex but can also be passed from an infected mother to a newborn during vaginal childbirth. Younger women and those with multiple sexual partners are among those at a higher risk for chlamydia infection.

Most people with chlamydia usually do not have any symptoms. When they are present, signs and symptoms may include discharge from the vagina in women (or penis in men), lower abdominal pain and lower back pain.

Chlamydia can be diagnosed through a urine test and by testing a fluid sample collected from the cervix or penis. The condition is easily treated with antibiotics. If left untreated, chlamydia can lead to a serious medical condition in women called pelvic inflammatory disease (PID), which can lead to infertility.

Although abstinence is the best way to prevent infection, the risk of transmission may be limited by practicing safer sex (e.g., using condoms, limiting the number of sexual partners). Those diagnosed with chlamydia should immediately inform their current and past sexual partners for testing. Treatment of partners limits the risk of complications and the spreading of infection to other individuals, including re-infection of the original patient.

Because it is more common in younger women, the Centers for Disease Control and Prevention recommends that women aged 25 years or younger receive a screening test annually for chlamydia whether or not they exhibit symptoms.

About chlamydia

Chlamydia is a bacterial infection of the genital tract spread through sexual contact. If untreated, it can result in various medical complications, including damage to a woman’s reproductive organs.

The disease affects both women and men, though reported cases for women greatly exceed those for men. Although it affects people in all age groups, it is particularly prevalent among teenagers and young adults.

Chlamydia is sometimes confused with gonorrhea, another sexually transmitted disease (STD) caused by a different type of bacteria. Gonorrhea and chlamydia have similar symptoms and, if untreated, can have similar complications. Both are treated with antibiotics, but a different type of antibiotic is used to treat each disease.

Chlamydia is a type of vaginitis, a disorder that causes swelling or infection of the vagina and vulva. In women, the bacteria that causes chlamydia often infects the cells of the cervix, but can spread to the uterus, fallopian tubes and ovaries. In men, the bacteria affect the urethra (the tube that carries urine from the bladder to outside the body), but can spread to the epididymis (the tube that carries the sperm from the testicles).

Chlamydia can be transmitted through vaginal, oral or anal sex. Since chlamydia can be transmitted by anal sex, women or men who have anal intercourse can become infected in the rectum (the last several inches of the intestines that ends at the anus). Although it is less common, chlamydia can also infect the throats of women and men who have oral sex with an infected partner

According to the National Women’s Health Information Center, there is no evidence that chlamydia is sexually transmitted between women who are sexually active with other women. However, large-scale studies have not been conducted to provide reliable information in this area. According to the Preventive Services Task Force (PSTF), the infection is most prevalent among U.S. women aged 20 to 25 years.

Pregnant women who have chlamydia can pass the infection to their babies during vaginal childbirth. Transmission to the newborn results from exposure to the mother’s infected cervix during birth. Infants who are exposed to the chlamydia bacteria may be born prematurely or develop neonatal conjunctivitis (a severe eye infection). Conjunctivitis in newborns can lead to serious complications including pneumonia (inflammation of the lungs), as drainage from the eye enters the nasal passages and infects the respiratory tract. Because of its potential severity, babies born to women with chlamydia are usually given medication in the form of a topical ointment that is applied to their eyes at the time of delivery. 

Chlamydia is the most common STD reported by physicians and other healthcare providers to the Centers for Disease Control and Prevention (CDC), with gonorrhea and syphilis second and third in frequency. However, there are other common STDs that physicians are not required to report to the CDC, such as the human papillomavirus (HPV) and genital herpes.

Estimates for the exact number of chlamydia cases vary. In 2006, more than 1 million cases of chlamydial infections were reported to the CDC. However, since many people are not aware of their infections and are not tested, health officials estimate that the actual number of infections is much higher. Statistics vary among individual health organizations, but most estimates fall within the range of 2.8 million to 4 million chlamydia infections per year. 

Because chlamydia can lead to serious medical problems, there has been increased attention and screening for the disease in recent years. According to the CDC, from 1987 through 2006, the reported rate of chlamydial infection in women increased from 50.8 cases to 347.8 cases per 100,000 people. The jump in reported figures is probably the result of increased screening, use of more sensitive diagnostic tests and improved reporting, as well as the continued high incidence of the disease.

Risk factors and causes of chlamydia

Chlamydia is caused by the bacteria Chlamydia trachomatis, which is found in vaginal fluids and semen. Chlamydia trachomatis can be passed through vaginal, anal or oral sex.

There are a number of risk factors for chlamydia. They are:

  • Age. Because the cervix of teenage girls and young women is not fully matured and more susceptible to infection, this population faces a particularly high risk for infection if sexually active. Women and adolescents through age 20 are at highest risk for the disease. But data from the Preventive Services Task Force (PSTF) indicate the infection is most common among U.S. women aged 20 to 25 years.

  • Number of sexual partners. The higher the number of sexual partners, the greater the risk of contracting chlamydia. The disease is more common in unmarried women due the absence of a long-term, single-partner relationship. One study showed that unmarried women ages 15 to 34 were seven times more likely to be infected than married women in the same age group.

  • Lack of or improper condom use. People who do not use condoms or use them inconsistently during sexual intercourse are at a greater risk of becoming infected.

  • A sex partner with a sexually transmitted disease (STD). People with a sexual partner with a sexually transmitted disease face a higher risk of getting chlamydia. Also, if the woman or her partner has a previous history of STDs, they are at a higher risk of developing chlamydia.

  • A sex partner who has not been treated. Women with chlamydia whose sexual partners have not been treated face a higher risk of becoming re-infected. A few studies have examined the use of “partner packs” in treatment. In these studies, infected women were given antibiotics for their sexual partners. While this reduced the rate of infection, there were questions of cost and problems with administering antibiotics to untested partners. This is not considered standard practice today, but is still under consideration.

Signs and symptoms of chlamydia

Chlamydia is often called a “silent” disease because about 75 percent of women and 50 percent of men infected have no symptoms, according to the National Women’s Health Information Center. If symptoms do occur, they usually appear within one to three weeks of exposure and may be mild.

Some signs and symptoms that may be present in women infected with chlamydia are:

  • Abnormal vaginal discharge

  • Burning sensation during urination

  • Lower abdominal or back pain

  • Nausea

  • Fever

  • Pain during intercourse

  • Bleeding between menstrual cycles

  • Proctitis (inflammation of the rectum)

Some signs and symptoms that may be present in men infected with chlamydia include abnormal discharge from the penis and burning sensation during urination. Complications among men are rare, but if untreated, chlamydia can lead to swollen or tender testicles or urethritis (infection inside the penis that can cause pain and difficulty urinating).

Patients diagnosed with chlamydia should inform their current and past sexual partners immediately. Testing and treatment of partners reduces the risk of complications and further spreading of the infection to other individuals.

Diagnosis methods for chlamydia

Chlamydia is diagnosed during a gynecological examination that includes a medical history and pelvic examination. A physician may discuss sexual history, including number of sexual partners, past history of sexually transmitted diseases and use of contraception.

Because chlamydia often produces no symptoms, the only conclusive way to diagnose chlamydia is a laboratory test. Since the Centers for Disease Control and Prevention recommends that all sexually active women aged 25 years or younger receive a screening test, women may be given a test even if they have no symptoms. In addition, the Preventive Services Task Force (PSTF) recommends that all pregnant women aged 25 years or younger be screened for the disease.

There are two types of tests that detect chlamydia:

  • Culture swab. For women, the physician may take a sample of vaginal discharge or mucous from the cervix with a swab. For men, the physician may insert a slim swab into the end of the penis to get a sample from the urethra. In some cases, a sample may be taken from the anus. The sample is then sent to a laboratory where it is studied for the presence of bacteria.
  • Urine test. This may be performed on women and men. After collecting a sample of urine, it is sent to a laboratory where it is studied for the presence of the chlamydia bacteria.

Treatment and prevention of chlamydia

Chlamydia can be easily treated and cured with antibiotics, which may be administered in a single dose or taken over the course of a week. Pregnant women can be treated effectively with antibiotics without harming their baby.

Patients should take all prescribed medication, even if symptoms are not present or disappear. Once chlamydia is diagnosed, all current and past sexual partners should be informed and treated to avoid reinfection. Patients and their sexual partners should avoid sexual contact with any individuals until treatment is completed.

Patients are not usually retested for chlamydia after completing the medication unless symptoms persist or reinfection is suspected.

There are a number of steps that can be taken to reduce the risk of getting chlamydia, including:

  • Practice abstinence. The best way to prevent infection is to practice abstinence or avoid having vaginal, anal or oral sex.

  • Use condoms. Using a condom correctly during every sexual encounter can lower the risk of contracting chlamydia as well as other STDs. For vaginal sex, a male latex condom or a female polyurethane condom should be consistently used. For anal sex, a male latex condom should be used. For oral sex, use a dental dam, which is a rubbery material that can be placed over the anus or the vagina before sexual contact.

  • Limit sexual partners. Having multiple sexual partners increases the risk of getting chlamydia and other sexually transmitted diseases. Maintaining a long-term, single-partner relationship is the best way to prevent contracting STDs. In addition, partners should honestly discuss their sexual histories to understand the possible risks.

Because teenagers and young adults are more susceptible to chlamydia infection, the Centers for Disease Control and Prevention recommends that sexually active women aged 25 years or younger be given a screening test annually for chlamydia whether they exhibit symptoms or not. An annual screening test is also recommended for older women with risk factors for chlamydia, such as a new sexual partner or multiple sexual partners.

Pregnant women may also be tested to prevent transmission of the infection to their babies. Pregnant women aged 25 years or younger should be routinely screened for the disease to prevent possible transmission of the infection to the baby during birth.

Consequences of chlamydia

If left untreated, chlamydia can progress to serious reproductive and other health problems with both short- and long-term consequences. Like the disease itself, the damage chlamydia causes is often “silent.” Complications in women from untreated chlamydia include:

  • Pelvic inflammatory disease (PID). Chlamydia can spread into the uterus or fallopian tubes and cause pelvic inflammatory disease. PID is an infection of the uterus, fallopian tubes and other reproductive organs. This happens in up to 40 percent of women with untreated chlamydia. Although it may cause no signs or symptoms, PID can damage the fallopian tubes, ovaries and uterus, including the cervix. Untreated PID can lead to abscesses in the fallopian tubes and ovaries. The infection can cause scarring that may lead to infertility. PID affects up to 1 million women in the United States, and half of all cases may be due to an untreated chlamydial infection.

  • Infertility (the inability to become pregnant after a year of continuous attempts). Chlamydial infection can scar the fallopian tubes, preventing eggs from being fertilized.

  • An ectopic or tubal pregnancy. In this condition, a fertilized egg becomes trapped during its passage and starts developing outside the uterus. This development usually occurs in the fallopian tube but sometimes in the cervix, ovary or abdomen. The embryo must be removed to prevent rupture of internal organs.

  • Chronic pelvic pain. Untreated chlamydia can result in scar tissue, which can cause continual pain. 

  • Human immunodeficiency virus (HIV). Women infected with chlamydia are more likely to get HIV if exposed to the virus. The reason for the increased risk is that chlamydia causes a spike in the number of leukocytes, immune system cells, at the site of infection. Some of these leukocytes are needed to fight the infection but HIV can infect the leukocytes.

  • Fitz-Hugh-Curtis syndrome. Patients with chlamydia sometimes develop Fitz-Hugh-Curtis syndrome, which involves inflammation of the liver. It is most often seen in cases of PID.

  • Reiter’s syndrome. Rarely, genital chlamydial infection can cause Reiter’s syndrome, which is arthritis (inflammation of the joints) that can be accompanied by skin lesions (abnormal tissue) and inflammation of the eye and urethra (the tube that carries urine from the bladder to the outside of the body).
  • Cervical cancer. Some studies show a greater risk of cervical cancer among women with current or past chlamydial infections.

In pregnant women, chlamydia infections may lead to premature delivery. Babies born to infected mothers can develop neonatal conjunctivitis (a severe eye infection), which can lead to pneumonia (inflammation of the lungs) and other serious complications.

Questions for your doctor regarding chlamydia

Preparing questions in advance can help patients have more meaningful discussions with their physicians regarding their conditions. Patients may wish to ask their doctor or healthcare provider the following questions about chlamydia:

  1. How do I know if I have chlamydia?
  2. How is chlamydia different from other STDs?
  3. What type of antibiotic will I be taking and for how long?
  4. How quickly will I see improvement after starting treatment?
  5. What happens if I don’t get treated immediately for chlamydia?
  6. How do I know which of my sexual partners are at risk for the infection?
  7. How will I know if my treatment has been successful?
  8. If I get chlamydia once, do I have a greater risk of getting it again?
  9. Will chlamydia affect my chances of becoming pregnant?
  10. If I’m pregnant, will I receive a different form of treatment for chlamydia?
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