Chlamydia is a bacterial infection passed through sexual contact, and it is the most commonly reported sexually transmitted infection in the United States. In 2024, nearly 944,000 cases were reported in women alone. What makes chlamydia particularly concerning is that most women who have it don’t know it, because the infection often causes no symptoms at all while quietly damaging the reproductive system.
How Women Get Chlamydia
Chlamydia spreads through vaginal, anal, or oral sex without a condom with someone who is infected. The bacteria infect the cells lining the cervix, and from there can spread upward into the uterus and fallopian tubes. Women can also develop a rectal infection from anal sex or from the bacteria spreading from the vagina. During childbirth, a pregnant woman with chlamydia can pass the infection to her baby.
You don’t need to have penetrative sex to contract chlamydia. Any contact between infected genital secretions and mucous membranes can transmit the bacteria. A partner doesn’t need to have visible symptoms to be contagious, which is one reason the infection spreads so easily.
Symptoms Most Women Experience
The majority of women with chlamydia have no symptoms at all, or only mild ones that are easy to dismiss. This is the single most important thing to understand about the infection: feeling fine doesn’t mean you’re clear.
When symptoms do appear, they typically include:
- A change in vaginal discharge (unusual color, texture, or amount)
- Bleeding between periods or after sex
- Pain or discomfort in the lower abdomen
- Burning sensation when urinating
- Itching around the vaginal area
These symptoms can overlap with yeast infections, urinary tract infections, or bacterial vaginosis, which is another reason chlamydia often goes undiagnosed without testing. Symptoms can show up anywhere from a few days to several weeks after exposure, but again, most women will notice nothing.
What Happens If It Goes Untreated
Even without symptoms, chlamydia can cause serious damage over time. About 10 to 15 percent of women with untreated chlamydia develop pelvic inflammatory disease, an infection of the uterus, fallopian tubes, and surrounding tissue. PID can happen silently too, meaning some women don’t realize it’s occurring until they face the consequences.
Those consequences are significant. Scar tissue can form inside the fallopian tubes, blocking them and making it difficult or impossible to get pregnant. The scarring also raises the risk of ectopic pregnancy, where a fertilized egg implants outside the uterus, a potentially life-threatening emergency. Some women develop chronic pelvic or abdominal pain that persists long after the original infection is gone. The damage to the reproductive tract is permanent, which is why catching chlamydia early matters so much.
Risks During Pregnancy
Chlamydia during pregnancy carries distinct risks for both the mother and baby. The infection has been linked to premature rupture of membranes, preterm labor and delivery, low birth weight, and fetal loss. Preterm birth is especially concerning given the health complications that come with prematurity.
Without treatment, vertical transmission rates from mother to baby during delivery are estimated at 50 to 70 percent. Among infants born to mothers with active, untreated chlamydia, 30 to 50 percent develop eye infections (conjunctivitis) and 10 to 20 percent develop pneumonia in the weeks after birth. Both conditions are treatable, but screening and treating chlamydia before delivery prevents them entirely.
How Chlamydia Is Diagnosed
The standard test for chlamydia is a nucleic acid amplification test, which detects the bacteria’s genetic material. These tests catch over 90 percent of infections while maintaining a specificity above 99 percent, meaning false positives are extremely rare. They detect 20 to 50 percent more infections than older testing methods like cultures.
For women, the preferred sample is a vaginal swab, which is just as accurate as a cervical swab and is less invasive. Many clinics offer self-collected vaginal swabs, so the process is quick and straightforward. Urine samples can also be used. Results typically come back within a few days.
Who Should Get Screened
Current guidelines recommend annual chlamydia screening for all sexually active women under 25, regardless of symptoms or relationship status. Women 25 and older should be screened if they have risk factors: a new sexual partner, more than one partner, a partner who has other partners, inconsistent condom use outside a mutually monogamous relationship, or a previous STI.
Because so many infections are silent, screening is the only reliable way to catch chlamydia before it causes damage. If you test positive and get treated, retesting about three months later is recommended because reinfection is common, especially if a partner wasn’t treated at the same time.
Treatment and Partner Management
Chlamydia is curable with a short course of antibiotics. The standard treatment is a seven-day course of oral antibiotics taken twice a day. You should avoid sex during treatment to prevent passing the infection back and forth. After completing the full course, the infection clears completely, though any reproductive damage that already occurred won’t reverse.
Treating your partner is just as important as treating yourself. If your partner isn’t treated, you’ll likely get reinfected the next time you have sex together. A practice called expedited partner therapy allows your doctor to write a prescription for your partner without requiring them to come in for a separate visit. This is especially useful when a partner is reluctant or unable to see a provider on their own. It doesn’t replace the ideal of having your partner get examined, but it’s a practical backup that reduces reinfection rates.
Why Reinfection Is So Common
Getting treated for chlamydia doesn’t give you any immunity. You can be reinfected immediately if you’re exposed again. Reinfection often happens because a sexual partner wasn’t treated, or because a new partner carries the bacteria without knowing it. Each reinfection carries the same risks as the first, including the potential for PID and fertility damage. This is why the three-month retest recommendation exists, and why partner treatment isn’t optional if you want to stay clear.