First the Facts

  • Trichomonas vaginalis (TV) is a sexually transmitted infection (STI)
  • TV is less common in the UK than other STIs
  • It is possible to have TV and not have any symptoms
  • If left untreated, it can cause long-term complications and you can pass it on to other people
  • If you have previously been treated for TV, you will not be immune – you can get it again

How Is Trichomonas Vaginalis Transmitted?

  • By having unprotected vaginal sex with someone who has the infection
  • This person might not have any symptoms and might not know they have TV
  • Anyone can have TV – you do not need to have had a lot of partners
  • Women who have sex with women can transmit TV by sharing sex toys
  • Transmission is through vaginal sex; you cannot get it through anal or oral sex
  • You cannot get TV through the saliva (e.g. kissing or sharing cutlery), hugging, toilet seats, or sharing towels

How Will I Know If I Have Trichomonas Vaginalis?

The best way to find out is to get a test.
Many people won’t have symptoms.

Possible symptoms if you have a penisPossible symptoms if you have a vagina
• Discharge from the tip of the penis
• Pain when passing urine
• Pain, redness or swelling of the foreskin (this is less common)
• Pain, redness, swelling or itching in and around the vagina (this can make sex uncomfortable)
• Unusual vaginal discharge
• Pain when passing urine
• Lower abdominal / pelvic pain
• Heavier or more painful periods, bleeding between periods or bleeding after sex (less common)

How Can I Protect Myself?

  • The use of condoms for vaginal sex

Where and When Can I Get a Test?

In the UK, TV is not routinely tested for if there are no symptoms. This is because rates of TV are lower than for other STIs.

  • You should get a test if:
    • A partner has told you they have TV
    • You have any of the symptoms listed above
    • You have been treated for another STI and you still have symptoms (see table above)
  • You can get a test at:
    • A sexual health or genitourinary medicine clinic
    • Some young person’s / contraception clinics
    • Some GP surgeries

If you have symptoms, you should attend a sexual health or genitourinary medicine clinic. 

  • In those with a vagina, the test is a self-taken swab from the lower part of the vagina
  • In those with a penis, the test is a urine sample. If there is discharge, a swab of this may be taken.

What Happens If I Have Trichomonas Vaginalis?

  • You will receive treatment with an antibiotic called metronidazole
  • You must not drink alcohol when taking metronidazole (and for 48 hours afterwards) as this can lead to vomiting
  • You will also be offered testing for other STIs if you have not already had this
  • You must tell your partner, as they will need to be tested and treated as well
  • Do not have sex until you have completed your treatment, as you can risk passing the infection back and forth. A condom can split, so it is better to not have sex at all for this time.
  • You usually do not need a follow-up test after treatment, providing you have taken the medication as advised. You might need a repeat test if your symptoms do not improve, or you have had unprotected sex before finishing your treatment.

What If I Don’t Get Treated for Trichomonas Vaginalis?

  • In those with a womb: It can spread to the womb and cause a pelvic infection.
  • If pregnant, having TV may increase the risk of premature labour or having a baby with a low birth weight.


Written by: Dr Nikki Kersey and Dr Paula Briggs
Last updated: January 2021

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