This page is general health information, not medical advice. It cannot tell you whether you have an infection. A clinician can, and the testing options on this site are a good place to start.

Many women who have a sexually transmitted infection (STI) notice nothing at all. Others notice a change in discharge, a burning feeling, or pain, and are not sure what it means. Both situations are common, and both are good reasons to get tested.

This guide explains the symptoms of STDs in women, how they overlap with everyday conditions, who should be screened even when they feel fine, and how to get an STD test for women in Denver at free or low cost. It is written for every woman, including cisgender and transgender women, women who have sex with women, and anyone with a cervix or vagina who is looking for clear information.

Key takeaways

Most STIs cause no symptoms, so feeling fine does not tell you what a test would show. The CDC says chlamydia and gonorrhea are often silent in women.
Signs worth a visit include unusual discharge, burning when you urinate, pain during sex, bleeding between periods, sores or bumps, and pelvic pain.
Bacterial STIs and trichomoniasis are curable with treatment from a clinician. HIV, herpes and HPV are not curable but are treatable and manageable.
Untreated chlamydia and gonorrhea can lead to pelvic inflammatory disease (PID), which can affect fertility. Testing and treatment lower that chance.
Severe pelvic pain, pain with fever, or pain during pregnancy needs same-day care.
In Denver, the Denver Sexual Health Clinic charges on a sliding scale from $0 to $70 for uninsured patients, and Denver Health outreach testing is free.

Why most STIs are silent
Symptoms of STDs in women, infection by infection
Symptoms that are not always an STI
Pelvic inflammatory disease and fertility
When to test, and when to be seen the same day
Where to get tested in Denver
What a visit involves and what happens next

Why most STIs are silent

Many people expect an infection to announce itself. With STIs, that often does not happen. The CDC STI Treatment Guidelines (2021) note that chlamydia is frequently asymptomatic, and the same is true of many gonorrhea infections in women. Trichomoniasis, herpes, HPV, syphilis and HIV can also pass without obvious signs for a long time.

This matters for a simple reason. An infection with no symptoms can still be passed to a partner, and it can still cause harm inside the body. Symptoms are not a reliable guide to whether a test is worthwhile.

A symptom check can only tell you what to bring up with a clinician. It cannot tell you whether you have an infection. Only a test can show that, and a clinician can explain the result.

Why women are sometimes missed

In the female body, the cervix is where chlamydia and gonorrhea often settle. A change there may cause no sensation. Mild changes in discharge or light spotting are easy to put down to a cycle, stress or a new medication. That is why routine screening exists.

Local context

Colorado is not an exception. The CDC's 2023 STI Surveillance state ranking tables report a chlamydia rate of 435.1 per 100,000 people in Colorado, with 25,571 cases. The same tables report 7,563 gonorrhea cases, a rate of 128.7 per 100,000. These are reported cases, so they reflect the infections that were found by testing.

Symptoms of STDs in women, infection by infection

Below is what the CDC describes for each common infection. Any of these signs can have other causes, and none of them confirms an STI on its own.

Chlamydia

Most women with chlamydia have no symptoms. When symptoms do appear, they can include:

Unusual vaginal discharge
A burning feeling when urinating
Pain during sex
Bleeding between periods or after sex
Lower abdominal or pelvic discomfort

Chlamydia is a bacterial infection. A clinician can treat it with prescribed antibiotics, and it is curable.

Gonorrhea

Gonorrhea looks a lot like chlamydia in women. The CDC notes that many women have no symptoms, and that mild symptoms are easy to mistake for a bladder or vaginal infection. Possible signs include increased discharge, burning with urination, and bleeding between periods.

Gonorrhea can also affect the throat and rectum, often without symptoms. If you have had oral or anal sex, tell the clinician so they can decide which sites to test. Gonorrhea is bacterial and curable with treatment from a clinician.

Trichomoniasis

Trichomoniasis is caused by a parasite. The CDC says many people have no symptoms. When there are symptoms, they can include itching, irritation, a change in discharge, and discomfort when urinating. It is curable with treatment from a clinician.

Genital herpes

Herpes often causes no noticeable signs, or signs so mild they are never connected to herpes. When symptoms do appear, the CDC describes painful blisters or open sores on or near the genitals or anus. Some people feel tingling, itching or burning before sores show up. A first outbreak can also come with flu-like feelings.

Herpes is not curable. It is treatable, and a clinician can prescribe medicine that reduces outbreaks and lowers the chance of passing it on. Many people live with it with little disruption.

Syphilis

Syphilis develops in stages. The CDC describes the first sign as a firm, round, usually painless sore, which can sit inside the vagina or on the cervix where it is easy to miss. The second stage can bring a skin rash, including on the palms and soles, along with other body-wide symptoms. Later stages can affect the heart, brain and other organs.

Syphilis is bacterial and curable, and earlier treatment is easier. Syphilis is also important during pregnancy, which is covered below.

HPV and genital warts

Human papillomavirus (HPV) is very common, and the CDC says most infections cause no symptoms and clear on their own. Some types cause genital warts, which are small bumps or clusters of bumps. Other types can cause cervical cell changes that are found through cervical screening rather than through symptoms.

HPV has no cure for the virus itself, but warts and cell changes can be treated, and a clinician can explain what a screening result means.

HIV

The CDC says some people have a flu-like illness, with fever, sore throat, rash or swollen glands, within a few weeks of HIV infection. Others have no symptoms for years. Because symptoms are unreliable, testing is the only way to know.

HIV is not curable, but it is very treatable. The CDC says that people who take HIV medicine as prescribed and reach an undetectable viral load do not pass HIV to sexual partners.

Hepatitis B and hepatitis C

These viruses affect the liver and can spread through sex and other routes. Many people have no symptoms for a long time. The CDC recommends hepatitis C screening for all adults at least once, and the Denver testing sites below list hepatitis C testing.

Symptoms that are not always an STI

Burning, itching and discharge are among the most common reasons for a clinic visit, and an STI is only one possible explanation. Other common causes include:

Yeast infections. They often bring itching and thick, white discharge.
Bacterial vaginosis. It is a shift in vaginal bacteria that can cause a thin discharge and odor. It is not classed as an STI, though it is more common in people who are sexually active.
Urinary tract infections. They can cause burning and a frequent need to urinate, with no link to sex.
Skin irritation. Soaps, shaving, detergents, or friction can cause itching and small bumps.
Hormone changes. Cycles, birth control, pregnancy and menopause can change discharge and cause spotting.

Because these look so similar, guessing is unreliable, and treating yourself for the wrong condition can delay care. A clinician can examine you and run the right tests. If symptoms came back after earlier treatment, say so, since that helps them look further.

Pelvic inflammatory disease and fertility

Pelvic inflammatory disease (PID) is an infection of the uterus, fallopian tubes or ovaries. The CDC explains that it often develops when bacteria, most often from untreated chlamydia or gonorrhea, travel upward from the cervix. PID can also have other causes.

PID can be mild or even unnoticed. When it does cause symptoms, they can include lower abdominal pain, fever, pain during sex, unusual discharge, and bleeding between periods.

How PID can affect fertility

PID can leave scar tissue in the fallopian tubes. The CDC lists possible long-term effects as chronic pelvic pain, ectopic pregnancy (a pregnancy that grows outside the uterus), and difficulty getting pregnant. The CDC also reports that about 1 in 8 women with a history of PID has difficulty getting pregnant.

This is not a prediction for any one person. Many women who test positive for chlamydia or gonorrhea and get treated never develop PID. The point is that early testing and treatment give the best chance of avoiding these problems. If you have had PID before, a clinician can talk through your own situation and any questions about future pregnancy.

Ectopic pregnancy is an emergency

Sudden, sharp pain on one side of the lower abdomen, especially with dizziness, shoulder pain, or vaginal bleeding when a pregnancy is possible, needs emergency care. Call 911 or go to an emergency room.

When to test, and when to be seen the same day

Routine screening, even without symptoms

The CDC and the U.S. Preventive Services Task Force (USPSTF) recommend:

Chlamydia and gonorrhea: yearly screening for sexually active women under 25, and for older women with risk factors such as a new partner, more than one partner, or a partner who has an STI.
HIV: the USPSTF recommends screening everyone ages 15 to 65 at least once, and more often if you have risk factors. The CDC recommends the same, and suggests at least yearly testing for people with ongoing risk.
Hepatitis C: the CDC recommends screening all adults at least once.
Syphilis, HIV and hepatitis B in pregnancy: the CDC recommends screening at the first prenatal visit.
Cervical cancer screening: the USPSTF recommends screening for women ages 21 to 65. The method and schedule depend on age, so ask your clinician which applies to you.

These are general recommendations. Your clinician may suggest a different plan based on your history, and women who have sex with women are included, since STIs can spread between any partners.

Good reasons to test sooner

A new partner, or a partner who may have had other partners
A partner who tells you they have an STI
Any symptom described above
Condom breakage or no barrier use
Before stopping condoms with a new long-term partner
You are planning a pregnancy

Timing: the window period

A window period is the time between an exposure and the point when a test can reliably detect an infection. For HIV, the CDC says a lab antigen and antibody test using blood from a vein can usually detect HIV 18 to 45 days after exposure. Tests using a finger prick can take 18 to 90 days, and antibody-only tests 23 to 90 days. For other infections, windows vary by test. A clinician can tell you whether to test now and again later.

A test done too early can miss an infection, so ask whether a repeat is needed. Do not wait to get care if you have symptoms.

See a clinician the same day if you have

Severe or worsening pain in your lower abdomen or pelvis
Pelvic pain with fever, chills, nausea or vomiting
Heavy or unexpected vaginal bleeding
Symptoms while pregnant
Painful sores that make urinating difficult
A possible HIV exposure in the past 72 hours

For a possible HIV exposure, post-exposure prophylaxis (PEP) is a medicine a clinician prescribes to lower the chance of HIV infection, and it works best when started quickly. The Denver Sexual Health Clinic asks people to call as soon as possible if they have been exposed to HIV in the past 72 hours. After hours or in an emergency, an emergency room can also start the process.

Testing and doxy-PEP

You may have read about doxycycline taken after sex to prevent bacterial STIs (doxy-PEP). The CDC's 2024 guidance recommends it for gay and bisexual men and transgender women who have had a bacterial STI in the past year. The CDC says there is not enough evidence to make the same recommendation for cisgender women. If you have questions, a clinician can talk through what fits your situation.

Where to get tested in Denver

Denver has several options, from free outreach testing to sliding-scale clinics. Before you go, call to check hours, appointment rules and eligibility, since these can change. The full local testing list compares options and costs in more detail.

Denver Sexual Health Clinic (Denver Public Health)

Operated by the Public Health Institute at Denver Health, this clinic is at 660 N. Bannock St., Pavilion L, 2nd Floor, Denver, CO 80204. Call 303-602-3540.

Services: STD testing, HIV and hepatitis C testing, PrEP, PEP and treatment.
Hours: Monday to Friday, 8 a.m. to 5 p.m., with a closure from 8 to 9 a.m. on the second Monday of each month.
Appointments: Required for all clinic visits.
Cost: Uninsured or out-of-network patients pay on a sliding fee scale from $0 to $70. The clinic says no one is denied care based on ability to pay.
Symptoms: Testing-only visits cover gonorrhea, chlamydia, syphilis, HIV and hepatitis C. The clinic says patients with symptoms need a provider visit, so mention your symptoms when you call.

Denver Health community outreach testing

Denver Health offers free, confidential walk-in STD, HIV and hepatitis C testing at rotating community locations around the Denver metro area, in English and Spanish. There is no single street address. Call or text 720-415-7075 for current locations. The outreach program does not provide physical exams or treatment, so if you have symptoms or a known exposure, contact the Denver Sexual Health Clinic instead. The program's hours are not published, so ask when you call.

HeyDenver (Colorado Health Network)

HeyDenver is at 822 E 19th Ave, Denver, CO 80218. Call 303-962-2880. It offers chlamydia and gonorrhea testing, rapid HIV testing, rapid syphilis testing, hepatitis C testing in some cases, and PrEP navigation. Office hours are Monday to Friday, 9 a.m. to 4 p.m. Walk-in testing happens on set days, and otherwise testing is by appointment. Colorado Health Network's own testing page lists this site as testing by appointment, so confirm before you go. The English page does not state a price, though the Spanish heading describes the testing as free (gratuitas).

Planned Parenthood of the Rocky Mountains, Park Hill Health Center

This center is at 7155 E 38th Ave, Denver, CO 80207, phone (303) 321-2458. The CDC GetTested directory lists STD, HIV and hepatitis C testing, rapid HIV testing, HPV vaccine and PrEP, with insurance and Medicaid accepted. It lists the site as no appointment needed. No prices or hours are published there, so contact the center about fees and eligibility.

Clinica Tepeyac

Tepeyac Community Health Center is at 2101 E 48th Ave, Denver, CO 80216, phone (303) 458-5302. The CDC GetTested listing shows STD, HIV and hepatitis C testing, HPV vaccine and PrEP, a sliding scale, and acceptance of insurance and Medicaid. An appointment is required. Hours are not listed, so call to confirm.

STRIDE Community Health Center, Oneida

STRIDE is at 2255 S Oneida St, Denver, CO 80224, phone 303-778-7433, open Monday to Friday, 7 a.m. to 5:30 p.m. STRIDE's women's health page lists STI testing and treatment, but the Oneida location page does not mention it, so call to confirm that it is offered there. Cost and walk-in policy are not published.

Free mail-in testing in Colorado

TestYourselfColorado.com, provided by Denver Public Health, offers free mail-in chlamydia and gonorrhea testing and an at-home HIV test once a year for Colorado residents 18 or older. The site says it is not for people who are pregnant or who have symptoms. If you have symptoms, a clinic visit is the better route.

Find more sites

The CDC's GetTested tool at gettested.cdc.gov lets you look up testing locations by ZIP code. It lists services, but check with each site for current hours and fees.

Teens and minors

Colorado law, C.R.S. 25-4-409, says a health-care provider consulted by a minor must, at the minor's request, perform an exam for a sexually transmitted infection, treat if needed, and discuss or prescribe preventive measures. Parental consent is not required, and the information is kept confidential except for child protection reporting. The statute sets no minimum age. A provider may involve a parent or guardian when the minor is 13 or younger.

Privacy and reporting

Under Colorado health department rules (6 CCR 1009-1), laboratories and providers report chlamydia and gonorrhea to public health within 4 days. Syphilis results are reported within 1 working day. These reports go to public health, which uses them to track infections and to help connect people with care.

What a visit involves and what happens next

Before you go

Call ahead for hours, appointments and any ID or insurance needs.
Write down your symptoms, when they began, and the date of your last period.
Make a list of medicines you take, and any allergies.
You do not need to be certain about anything. Clinicians see these questions every day.

What the clinician may ask

You may be asked about partners, the kinds of sex you have, and any past STIs. These questions help the clinician choose the right tests, including whether to swab the throat or rectum. Honest answers lead to better care, and the questions are not a judgment.

Common tests

Urine or swab tests for chlamydia and gonorrhea. The CDC notes that a vaginal swab is the preferred sample for women, and it can often be collected by the patient.
Blood tests for HIV, syphilis and hepatitis.
A swab of a sore for herpes, when sores are present.
Cervical screening (Pap test, HPV test or both) on the schedule your clinician recommends.

If a result is positive

A positive result is information, and it is a very common one. For bacterial infections and trichomoniasis, a clinician prescribes treatment that cures them. Follow the instructions you are given and ask whether to avoid sex for a period of time. The CDC also recommends that partners get tested and treated so that infection does not pass back and forth. A clinician or health department staff can help you with that conversation.

For HIV, herpes and HPV, a positive result starts a conversation about management. Treatment for HIV is very effective, and people with herpes or HPV can often go long periods without problems. Ask your clinician about what comes next, and about whether a retest is advised after treatment.

During pregnancy

Syphilis can pass to a baby during pregnancy and is called congenital syphilis. Colorado's health department rules (6 CCR 1009-1, Regulation 12) require providers treating anyone who is pregnant to offer syphilis testing at the first prenatal visit or in the first trimester, again at 28 to 32 weeks, and at delivery, unless a documented test already met the requirement or the patient declines. The CDC's 2023 state tables report 51 cases of congenital syphilis in Colorado. Prenatal testing and treatment are the way to prevent it.

Prevention options

Condoms and dental dams lower the chance of many STIs. Regular testing, talking with partners, and the HPV vaccine also help. PrEP is a medicine a clinician prescribes to lower the chance of getting HIV. The Denver Sexual Health Clinic says it will meet with anyone who wants to start PrEP, and HeyDenver offers PrEP navigation at 303-962-2880.

Next step

If you have symptoms, have a new partner, or simply have not been tested in a while, a visit is a reasonable next step. For a quick start, call the Denver Sexual Health Clinic at 303-602-3540, or call or text 720-415-7075 to find a free outreach testing site. Either way, you are doing something good for your health.

STD Symptoms in Women: Signs, When to Test and Where in Denver