Chlamydia often causes no symptoms at all. Roughly 70 to 80% of women and up to 50% of men with the infection never notice anything wrong, which is why it spreads so easily and why routine screening matters more than waiting for something to feel off. When symptoms do appear, they differ depending on the site of infection and can range from mild discomfort to signs that are easy to mistake for something else entirely.
Symptoms in Women
When chlamydia does cause symptoms in women, they tend to show up in the lower reproductive tract first. The most common signs include:
- Unusual vaginal discharge that looks or smells different from what’s normal for you
- Burning or pain when urinating
- Bleeding between periods or spotting and cramping throughout the month
- Bleeding after sex
- Pain in the lower abdomen or pelvis
These symptoms can be subtle. A slight change in discharge or occasional spotting is easy to write off, especially if you’re not expecting an infection. That’s part of what makes chlamydia tricky: the symptoms that do appear often mimic a urinary tract infection or hormonal irregularity, so they don’t always prompt a visit for STI testing.
Symptoms in Men
Men are more likely than women to notice something, though half still have no symptoms. When signs do develop, they typically include:
- Discharge from the penis, which may be clear, white, or slightly cloudy
- A burning sensation when urinating
- Pain or swelling in one or both testicles, though this is less common
Testicular pain or swelling suggests the infection has reached the epididymis, the coiled tube behind each testicle that stores sperm. This is a sign to get tested promptly, since untreated inflammation there can affect fertility over time.
Rectal and Throat Infections
Chlamydia doesn’t only infect the genitals. Rectal chlamydia can develop from receptive anal sex or from the bacteria spreading from a nearby infected site like the vagina. Rectal infections often cause no symptoms, but when they do, you may notice rectal pain, discharge, or bleeding.
Throat (pharyngeal) chlamydia is also possible through oral sex, though it rarely causes noticeable symptoms. When it does, it may feel like a mild, persistent sore throat. Because these infections are so often silent, they’re easy to miss unless your provider specifically swabs those areas during testing.
Why Most People Don’t Know They Have It
The high rate of asymptomatic infection is the defining challenge with chlamydia. You can carry and transmit the bacteria for weeks or months without any indication. This is why the U.S. Preventive Services Task Force recommends annual screening for all sexually active women age 24 and younger, and for older women with risk factors like a new partner, multiple partners, or inconsistent condom use. For men, there isn’t a universal screening recommendation yet, though many providers test men who have symptoms or known exposure.
If your sexual history includes new or ongoing risk factors since your last negative test, screening is a reasonable step regardless of whether anything feels wrong.
How Chlamydia Is Tested
Testing is straightforward. You’ll either provide a urine sample or have a swab taken from the potentially infected area (genitals, rectum, or throat). For the urine test, you collect the very first part of your urine stream, and you’ll need to avoid urinating for about two hours beforehand to get an accurate result. In many cases, you can swab yourself rather than having a provider do it.
At-home test kits are also available. You collect your own sample and mail it to a lab. Some rapid tests can return results in 90 minutes or less, though most standard lab tests take a day or two.
What Happens If Chlamydia Goes Untreated
Left alone, chlamydia can move deeper into the reproductive system and cause serious problems. In women, the most significant risk is pelvic inflammatory disease (PID), an infection of the uterus, fallopian tubes, or ovaries. PID doesn’t always announce itself loudly. You might have mild lower abdominal pain, fever, foul-smelling discharge, painful sex, or no noticeable symptoms at all.
The damage from PID, however, can be lasting. Scar tissue can form inside and around the fallopian tubes, leading to blocked tubes, ectopic pregnancy (where a fertilized egg implants outside the uterus), chronic pelvic pain, or infertility. These complications can develop even from a single episode of PID, and the risk increases with repeated infections.
In men, untreated chlamydia can lead to epididymitis (inflammation and pain in the testicles) and, less commonly, to fertility issues. In rare cases, both men and women can develop reactive arthritis, a condition that causes joint pain and swelling triggered by the infection.
Chlamydia in Newborns
Babies born to mothers with an active chlamydia infection can pick up the bacteria during delivery. The most common result is an eye infection (conjunctivitis) that typically appears 5 to 14 days after birth. It usually starts in one eye with watery discharge that becomes thicker and sometimes bloody, then spreads to the other eye within about a week.
If the infection isn’t treated, the bacteria can colonize the baby’s throat and lungs, potentially causing pneumonia. Eye drops given at birth to prevent other types of newborn eye infections are not effective against chlamydia specifically, which is one reason prenatal chlamydia screening is standard practice.
When Symptoms Appear After Exposure
For those who do develop symptoms, they generally show up within one to three weeks after exposure. But there’s no reliable window. Some people notice something within days, while others may not develop symptoms for months, if ever. The absence of symptoms during any particular timeframe doesn’t rule out infection, which circles back to the core reality of chlamydia: testing is the only way to know for sure.