References UK clinical guidance from the NHS, the British HIV Association (BHIVA), and the British Association for Sexual Health and HIV (BASHH). Last updated: April 2026.
Trichomoniasis is a common STI that is easily cured with antibiotics. If left untreated, it can cause persistent symptoms, complications in pregnancy, increased vulnerability to other infections including HIV, and can continue to spread to sexual partners. Because many people with trichomoniasis have no symptoms, the infection can go unnoticed and untreated for a long time.
Here’s what can happen without treatment.
Order a discreet home STI test
What Is Trichomoniasis?
Trichomoniasis is caused by a tiny parasite called Trichomonas vaginalis. It’s transmitted through unprotected vaginal sex, and occasionally through shared sex toys. It’s one of the most common curable STIs worldwide.
Consequences of Leaving It Untreated
| Consequence | Detail |
|---|---|
| Persistent symptoms | Discharge, itching, pain can continue or worsen over time |
| Pelvic inflammatory disease | Can contribute to PID, though less commonly than chlamydia |
| Pregnancy complications | Preterm birth, low birth weight, premature rupture of membranes |
| Increased HIV risk | Trichomoniasis raises vulnerability to acquiring and transmitting HIV |
| Cervical inflammation | Chronic cervicitis |
| Urethral inflammation in men | Non-gonococcal urethritis |
| Infertility | Rare but possible through complications |
| Ongoing transmission | You continue to infect sexual partners |
Pregnancy Risks
Untreated trichomoniasis during pregnancy has been linked to:
- Preterm delivery
- Premature rupture of membranes
- Low birth weight
- In rare cases, transmission to the baby during birth
Pregnant women with trichomoniasis should be treated to reduce these risks. Metronidazole is considered safe in pregnancy.
The HIV Connection
Trichomoniasis causes inflammation in the genital tract. This makes it easier for HIV to enter the body (for HIV-negative people) and easier for HIV to be passed on (for people living with HIV). Treating trichomoniasis reduces this risk.
Symptoms
Not everyone has symptoms, but when they occur they include:
- Frothy, yellow-green vaginal discharge with a foul smell
- Genital itching or irritation
- Pain during urination or sex
- Lower abdominal discomfort
- In men: discharge, burning on urination, or often no symptoms
Treatment
Trichomoniasis is easily cured with:
- Metronidazole 400-500mg twice daily for 5-7 days, or
- Single 2g dose of metronidazole
Alcohol should be avoided during treatment and for 48 hours after, as metronidazole can cause severe reactions with alcohol.
Partner Treatment
Current partners should be treated at the same time to prevent reinfection. Sexual health clinics can help with confidential partner notification.
Read more: What is trichomoniasis? | Trichomoniasis vs chlamydia | What is HIV?
Frequently Asked Questions
Can trichomoniasis go away on its own?
Rarely. Most infections persist without treatment. Waiting risks complications and ongoing transmission.
Will trichomoniasis always cause symptoms?
No. Up to half of people with trichomoniasis have no symptoms, which is why regular STI testing is important.
Can I drink alcohol during treatment?
No. Metronidazole can cause a severe reaction with alcohol. Avoid alcohol during treatment and for at least 48 hours after finishing.
Related reading
- What Is Trichomonal Vaginitis?
- Blood Test for Syphilis, Hepatitis B and Hepatitis C
- Can You Get an STI From Being Fingered?
- Can You Catch an STI From a Toilet Seat?
- Can You Clear HPV Once You Have It?
Sources
- NHS — Sexual health conditions
- BASHH — UK clinical guidelines for STI management
- British HIV Association (BHIVA) — HIV treatment guidelines
- Terrence Higgins Trust — sexual health information
- UK Health Security Agency — STI surveillance data
Steve Page is a recognised expert on Sexually Transmitted Diseases (STDs) and STD treatments, having published numerous articles in peer-reviewed journals and presented his research at conferences around the world. He has an in-depth understanding of the latest medical research on STDs, and is an advocate for the development of new treatments and protocols to improve the health of those affected. In addition to his research, he has dedicated his career to understanding the causes and symptoms of STDs, as well as how to best treat those impacted.
