Chlamydia infections in women

Chlamydia is a common sexually transmitted infection caused by the bacterium Chlamydia trachomatis. In women, it most often infects the cervix, which is the opening to the uterus. It can also infect the urethra, rectum, and, less commonly, the throat.

Many women with chlamydia have no symptoms. An infection can therefore remain unnoticed and be passed to sexual partners. Without treatment, bacteria may travel from the cervix into the uterus and fallopian tubes. This can cause pelvic inflammatory disease, or PID, and may affect future fertility.

Chlamydia is curable with antibiotics like amoxicillin or doxycycline. Testing is usually simple, and early treatment can prevent most complications. Because treatment does not create immunity, a person can become infected again after treatment.

Although this article focuses on women, testing and treatment may also apply to transgender and nonbinary people based on their anatomy, sexual exposures, and pregnancy potential. A clinician can recommend testing that fits an individual's needs.

Most chlamydia infections in women do not cause noticeable symptoms. When symptoms occur, they may begin several weeks after exposure. They can be mild and may be mistaken for a urinary tract infection, vaginal irritation, or a change in the menstrual cycle.

Possible symptoms include:

• Vaginal discharge that is new or different
• Burning or pain during urination
• Bleeding between periods or after sex
• Pain during vaginal sex
• Lower abdominal or pelvic pain
• Rectal pain, discharge, or bleeding after rectal exposure

A throat infection usually causes no symptoms. If symptoms do occur, they may include throat discomfort, but a sore throat has many more common causes.

Symptoms alone cannot confirm chlamydia. Other infections and noninfectious conditions can cause similar concerns. Testing is needed to find the cause.

Pelvic pain with fever, vomiting, unusual discharge, or pain during sex may indicate PID and should be assessed promptly. Contact a healthcare professional the same day if possible, especially during pregnancy.

Seek emergency care for severe or worsening pelvic or abdominal pain, fainting, marked weakness, shoulder pain, or heavy vaginal bleeding. These symptoms can have causes other than chlamydia, including an ectopic pregnancy, in which a pregnancy grows outside the uterus.

Chlamydia spreads mainly through vaginal, anal, or oral sex with someone who has the infection. Transmission can occur even when the infected person has no symptoms and does not ejaculate. Shared sex toys may also carry infected fluids if they are not cleaned or covered with a new condom between users.

A pregnant person can pass chlamydia to a baby during childbirth. This may cause an eye infection or pneumonia in the newborn. Chlamydia is not spread through ordinary contact such as hugging, sharing food, using toilet seats, or swimming in a pool.

Anyone who is sexually active can get chlamydia. Factors associated with a higher chance of infection include:

• Being sexually active and younger than 25
• Having a new sexual partner or more than one partner
• Having a partner who has other sexual partners
• Having a current or previous sexually transmitted infection
• Having sex without condoms or other barriers
• Having a sexual partner diagnosed with chlamydia

These factors do not mean that someone has chlamydia. They help clinicians decide when screening may be useful. A mutually monogamous relationship lowers risk only when both partners are uninfected and remain monogamous.

Condoms and internal condoms reduce the chance of transmission when used correctly for the entire sexual contact. Barriers do not eliminate risk completely because they may not cover every exposed area or may be used inconsistently.

Chlamydia is usually diagnosed with a nucleic acid amplification test, often called a NAAT. This highly sensitive test looks for genetic material from the bacteria.

For women, a vaginal swab is commonly used. In many clinics, patients can collect this swab themselves in private. A clinician may instead collect a vaginal or cervical sample during an examination. A urine sample can also be tested, although a vaginal swab may be preferred in some settings.

Testing should match the areas that may have been exposed. A rectal swab may be appropriate after anal sex, and a throat swab may be considered after oral exposure. A urine or vaginal test will not reliably detect an infection limited to the rectum or throat.

A pelvic examination is not always needed for routine screening. It may be recommended when there is pelvic pain, bleeding, unusual discharge, pregnancy-related concern, or possible PID.

The U.S. Preventive Services Task Force recommends screening for sexually active women age 24 or younger and for women age 25 or older who have an increased risk of infection. Pregnancy screening depends on age and risk factors. Clinicians may recommend testing at the first prenatal visit and, for people with continued risk, again later in pregnancy.

If chlamydia is found, testing for other sexually transmitted infections may be offered. This often includes gonorrhea, HIV, and syphilis testing. A pregnancy test may also affect treatment and follow-up decisions.

Chlamydia is treated with prescription antibiotics. The specific medicine depends on factors such as pregnancy, the site of infection, allergies, other medicines, and whether the full treatment course can be completed.

For most nonpregnant adolescents and adults, current U.S. guidance generally prefers a course of doxycycline. Other antibiotics may be used in certain situations. During pregnancy, clinicians select medicines with established pregnancy safety, commonly azithromycin. A healthcare professional should choose the appropriate treatment rather than using leftover or shared antibiotics.

Take the medicine exactly as directed and complete the full course, even if symptoms improve. Missing treatment can allow the infection to continue. Contact the prescribing clinician if vomiting, side effects, or another problem makes it difficult to finish the medicine.

Sex should be avoided until treatment has had time to work. Under Centers for Disease Control and Prevention guidance, this means waiting until seven days after a single-dose treatment or until a seven-day course has been completed. Any symptoms should also have resolved, and sexual partners should have been treated. This includes vaginal, anal, and oral sex.

Recent sexual partners need evaluation, testing, and usually treatment even if they have no symptoms or their test results are not yet available. This helps prevent reinfection and stops further spread. A clinician or public health service can explain how far back to notify partners.

In some locations, a clinician may provide medicine or a prescription for a partner without examining that person first. This is called expedited partner therapy. Availability and legal requirements vary. Partners should still seek medical care when possible, particularly if they have symptoms, are pregnant, or may have another infection.

Treatment usually cures the current infection, but it does not repair scarring that has already developed. It also does not protect against future chlamydia infections. Condoms, regular testing when recommended, and ensuring that partners are treated can reduce the chance of reinfection.

Untreated cervical chlamydia can spread into the upper reproductive organs and cause PID. PID may be mild or have no clear symptoms, yet inflammation can still damage the fallopian tubes.

Possible long-term effects include difficulty becoming pregnant, long-lasting pelvic pain, and a higher risk of ectopic pregnancy. An ectopic pregnancy cannot develop normally and may become an emergency if it causes internal bleeding.

Chlamydia can also cause inflammation around the liver as part of PID, sometimes called Fitz-Hugh–Curtis syndrome. This may cause pain in the upper right abdomen. Reactive arthritis, which can involve joint pain and eye or urinary symptoms, is an uncommon complication.

During pregnancy, untreated infection has been associated with pregnancy complications and infection in the newborn. Appropriate prenatal testing and treatment reduce these risks.

Having chlamydia may also make it easier to acquire or transmit HIV when exposure occurs. This is one reason clinicians often offer HIV testing after a chlamydia diagnosis.

Not everyone with untreated chlamydia develops complications, and a positive test does not show whether reproductive organs have been damaged. A clinician can assess symptoms and discuss whether further evaluation is needed.

Most nonpregnant people do not need a test immediately after completing treatment if they took the medicine correctly, symptoms have resolved, and reinfection is not suspected. Testing too soon can detect genetic material from dead bacteria and produce a positive result even though treatment worked.

Testing again about three months after treatment is generally recommended because repeat infections are common. If that timing is not possible, retesting should occur when medical care is next available within the following year. This is routine follow-up, not a sign that treatment was expected to fail.

During pregnancy, a test of cure is recommended about four weeks after treatment to confirm that the infection has cleared. Pregnant patients are also retested later because repeat infection can affect both parent and baby.

Arrange a routine or prompt follow-up appointment if:

• Symptoms continue after treatment
• Medicine was not taken as directed
• Sex occurred before both partners completed treatment
• A partner was not treated
• New exposure may have occurred
• There are questions about pregnancy, fertility, or other STI tests

Seek same-day medical advice for fever with pelvic pain, worsening lower abdominal pain, vomiting, or new pain during sex. Seek emergency care for fainting, severe abdominal or pelvic pain, heavy bleeding, or concerning symptoms during a possible pregnancy.