Trichomoniasis: Symptoms, Risks, and Treatment
You have been tested for BV. Tested for yeast. Maybe tested for chlamydia and gonorrhea. But there is one common infection that gets left off a lot of standard panels, skipped at routine visits, and almost never talked about openly even though it affects millions of women every single year.
That infection is trichomoniasis. And the reason it stays so hidden is not because it is rare. It is because most women who have it do not have obvious symptoms and most providers do not automatically test for it unless you specifically ask.
Trichomoniasis is the most common curable sexually transmitted infection in the world. In the United States alone, an estimated 2.6 million people are infected at any given time. Yet it is wildly under-discussed compared to chlamydia, gonorrhea, and herpes. Understanding what it is, how it spreads, what symptoms it causes when it does cause them, and how it is treated gives you one more powerful tool for protecting your vaginal and reproductive health.
What Is Trichomoniasis?
Trichomoniasis often called "trich" is a sexually transmitted infection caused by a tiny parasite called Trichomonas vaginalis. It is not a bacterium and it is not a virus. It is a single-celled protozoan parasite that lives in the urinary tract and genital area.
In women, trich typically infects:
The vagina.
The urethra.
The cervix.
The bladder in some cases.
In men, it most commonly infects the urethra and is often completely asymptomatic, which is one reason it spreads so easily partners may not know they are carrying it.
Trich is passed through skin-to-skin genital contact during sexual activity. It does not require penetration to spread and cannot be caught from toilet seats, towels, or casual contact.
How Common Is Trichomoniasis?
More common than most people realize.
The CDC estimates approximately 2.6 million infections occur in the United States at any given time.
Globally it is the most common non-viral sexually transmitted infection.
It is more prevalent in women than in men.
Risk increases with multiple sexual partners, inconsistent condom use, and prior STI history.
Part of why the numbers are high is that most infected people up to 70% of women with trich have no symptoms at all. They are not seeking testing because they feel fine, and in the meantime they may pass it to partners without knowing.
Symptoms of Trichomoniasis in Women
When symptoms do appear, they usually show up within 5 to 28 days of exposure but they can appear earlier or much later.
Common symptoms include:
Abnormal discharge often described as frothy, foamy, or bubbly; color ranges from yellow to green to gray.
Strong, unpleasant vaginal odor often described as fishy or musty.
Itching, burning, or redness inside the vagina and on the vulva.
Pain or burning with urination often confused with a UTI.
Discomfort during sex pain or soreness during penetration.
Lower abdominal discomfort not always present but possible.
Many women initially mistake trich for BV or a yeast infection because the discharge and odor can overlap. However, frothy yellow-green discharge combined with odor and significant irritation is more specific to trichomoniasis than to either BV or yeast.
Why Trichomoniasis Gets Missed
There are several reasons trich is consistently under-diagnosed:
Most people are asymptomatic
Up to 70% of women with trichomoniasis have no obvious symptoms. If you feel fine, you are unlikely to seek testing specifically for trich.
It is not always on standard STI panels
Many routine STI screenings automatically include chlamydia and gonorrhea but do not include trichomoniasis unless it is specifically requested. If you have never asked for a trich test by name, you may never have been tested.
Symptoms overlap with BV and yeast
When symptoms do appear, they mimic other vaginal infections closely. Women are often treated repeatedly for BV or yeast with no improvement never realizing trich is the actual cause.
Mild infections are easy to dismiss
Light or intermittent discharge and mild odor may be written off as "just BV again" or "my normal pattern" rather than prompting investigation.
How Trichomoniasis Is Diagnosed
Standard diagnosis is done through testing not just symptoms alone.
Testing options include:
NAAT (Nucleic Acid Amplification Test) the gold standard; most sensitive and accurate; can be done from a vaginal swab or urine sample.
Rapid antigen test available in some clinics; results in minutes; slightly less sensitive than NAAT.
Wet prep microscopy a vaginal swab examined under a microscope in the clinic; can detect moving parasites but has lower sensitivity than NAAT.
Culture less commonly used but accurate.
If you have recurring vaginal symptoms, unexplained odor, burning with urination, or have been treated multiple times for BV without lasting results, asking specifically for trichomoniasis testing is completely appropriate and important.
How Trichomoniasis Is Treated
The good news is that trichomoniasis is completely curable with antibiotics.
Standard treatments are:
Metronidazole 2g as a single oral dose (most common), or 500mg twice daily for 7 days.
Tinidazole 2g as a single oral dose; an alternative to metronidazole with a similar cure rate and sometimes fewer gastrointestinal side effects.
Both medications are equally effective for uncomplicated trichomoniasis. Cure rates with proper treatment are very high above 90%.
Important notes about treatment:
Avoid alcohol during metronidazole treatment and for 24–48 hours after your last dose due to the risk of a severe reaction.
Avoid alcohol during tinidazole treatment and for 72 hours after your last dose.
Abstain from sex during treatment and until you and your partner(s) have both finished treatment and symptoms have resolved.
Both partners must be treated at the same time. This is non-negotiable for preventing reinfection. If your partner is not treated, you will likely become reinfected even after a successful course.
What Happens If Trichomoniasis Is Not Treated?
Untreated trich can lead to significant health consequences beyond ongoing discomfort.
Increased HIV risk
Trichomoniasis causes inflammation of genital tissues that significantly increases the risk of both acquiring and transmitting HIV if exposed. Women with trich are estimated to be up to 2-3 times more likely to acquire HIV if exposed.
Pregnancy complications
Trich during pregnancy is associated with:
Preterm birth.
Low birth weight.
Premature rupture of membranes.
Pregnant women should be tested and treated for trichomoniasis if detected, though the timing and regimen are guided by the provider.
Ongoing inflammation and discomfort
Even without dramatic symptoms, ongoing low-grade trichomoniasis causes chronic inflammation that may contribute to recurrent vaginal symptoms, difficulty maintaining normal vaginal pH, and vulnerability to other infections including BV.
Contribution to PID
While trichomoniasis is not the classic cause of pelvic inflammatory disease the way chlamydia and gonorrhea are, the chronic inflammation it causes may increase susceptibility to upper tract infections when combined with other organisms.
Trichomoniasis, BV, and the Vaginal Microbiome Connection
One of the reasons trich matters so much in the context of BV is that the two conditions frequently co-occur and reinforce each other.
Trichomoniasis raises vaginal pH.
Higher pH promotes BV-associated bacteria.
BV inflammation makes the vaginal environment more hospitable to Trichomonas vaginalis.
Women with trich are significantly more likely to also have BV, and women with BV are more vulnerable to acquiring trich. If you have been treated for BV multiple times with partial or temporary results and have never been specifically tested for trich, this is an important missing piece to discuss with your provider.
Trichomoniasis in Pregnancy
Trichomoniasis during pregnancy deserves special mention.
It is associated with preterm labor and low birth weight.
Oral metronidazole is the recommended treatment and is considered safe in pregnancy.
The single 2g dose is generally used.
Some clinicians prefer to delay treatment until after the first trimester to minimize any theoretical risk, though evidence supports safety throughout pregnancy.
If you are pregnant and have vaginal symptoms any unusual discharge, odor, burning, or irritation trich testing is important, not just BV and yeast testing.
Can You Get Trichomoniasis Again?
Yes. Having trichomoniasis once does not make you immune. Reinfection is common, particularly when:
Partners are not treated simultaneously.
You have multiple partners.
Condoms are used inconsistently.
Studies suggest that up to 17% of women are reinfected within 3 months of treatment. This is almost always due to an untreated partner reintroducing the parasite, not treatment failure.
Protecting Yourself Going Forward
Prevention strategies for trichomoniasis overlap with general sexual health best practices:
Use condoms consistently. Condoms significantly reduce trich transmission risk, though they do not eliminate it entirely since the parasite can live on skin not covered by a condom.
Get tested regularly. If you are sexually active with new or multiple partners, include trich in your regular STI screening not just chlamydia and gonorrhea.
Make sure partners are tested and treated. Always. Both partners treating simultaneously is the only way to break the reinfection cycle.
Be honest with your provider about your symptoms and sexual history. You cannot get tested for something your provider does not know to look for.
When to Ask for a Trichomoniasis Test
Ask specifically for trich testing if:
You have recurring vaginal symptoms that have not fully resolved with BV or yeast treatment.
You notice frothy, yellow-green, or foamy discharge.
You have an unexplained strong vaginal odor.
You have burning with urination without a confirmed UTI.
You have a new sexual partner.
You have not been tested for trich in the past year and are sexually active.
You are pregnant with vaginal symptoms.
You have every right to say "I want to be tested for trichomoniasis specifically" at any appointment. You do not need to wait for a provider to suggest it.
“This article is based on current medical guidance and research from the following trusted sources:”
Resources & Sources
Centers for Disease Control and Prevention (CDC) Trichomoniasis: Detailed Fact Sheet:
cdc.gov/std/trichomonas
Mayo Clinic Trichomoniasis: Symptoms and Causes:
mayoclinic.org/diseases-conditions/trichomoniasis
National Institutes of Health (NIH) / PubMed Research on Trichomonas vaginalis and vaginal health:
pubmed.ncbi.nlm.nih.gov
American College of Obstetricians and Gynecologists (ACOG) Vaginitis including trichomoniasis:
acog.org
World Health Organization (WHO) Sexually Transmitted Infections: Trichomoniasis:
who.int/news-room/fact-sheets/detail/sexually-transmitted-infections
Have you ever been tested for trichomoniasis specifically or did you only find out about it after repeated BV treatments didn't work? Share in the comments. Your experience might be exactly what another woman needs to read.
Author
Becky Freeman is the founder of BVTalks® and Bee Vee Clean. She focuses on women’s intimate health, vaginal microbiome education, and creating practical, easy-to-understand content for everyday care.
Disclaimer: This post is for educational purposes only and is not a substitute for professional medical advice. Always consult your healthcare provider for diagnosis and treatment.
