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What is Trichomoniasis?

Often referred to as ‘trich’, trichomoniasis is a common sexually transmitted disease (STD). The World Health Organisation estimates the rate of newly infected people at 170 million per year.
Trichomoniasis is caused by a small protozoan (single-celled) parasite called Trichomonas vaginalis. This organism can infect the vagina, urethra and beneath the foreskin of the penis.

Getting a diagnosis

If you think you may have an STD, visit your GP or sexual health/genitourinary medicine clinic as soon as possible. A healthcare professional will conduct a genital examination to distinguish any symptoms from those of chlamydia, herpes or gonorrhoea. You may be asked to provide a urine sample or a swab will be taken from the vagina or penis and sent off to the lab to confirm the diagnosis under a microscope. A swab is a very quick and painless procedure. The results are sometimes available within days and usually no longer than 10 days. If you have no symptoms but think you might have caught an STD, regular STD screening is beneficial to ensure any STDs are identified as early as possible. For instance, if you have had unprotected sex with a new partner or have recently been diagnosed with a different STD.

What are the symptoms?

Symptoms usually develop within a week to a month of infection, however, it is non-symptomatic in approximately two-thirds of people. It is not known why some people don’t present with any symptoms; it is thought to possibly be related to a person’s overall health and age. Symptoms can range from mild irritation to severe inflammation.

Symptoms in women

Women may experience discomfort during urination or sex, a change in vaginal discharge consistency, colour or smell) or itchiness around the vagina and inner thighs.

Symptoms in men

Men may experience pain during urination or ejaculation, more frequent urination, soreness or swelling of the penis or discharge from the penis.


Trichomoniasis can be successfully treated with an antibiotic called metronidazole, which is taken orally twice a day for 5-7 days. You will need to inform any current or recent sexual partners so they can also be tested and treated if necessary (this can be done confidentially on your behalf by the clinic). Testing and treatment are usually free of charge at clinics, whereas your GP will charge the small cost of a prescription for the course of antibiotics. If you have presented with symptoms, treatment may be started before the results are confirmed. This treatment is very effective if taken as instructed, completing the full course and avoiding alcohol until treatment is complete. It is also advisable to avoid intercourse during treatment and for 7 days after the last antibiotic is taken to avoid reinfection or transmission. Any symptoms should start to improve within a few days of starting antibiotics.

How does trichomoniasis spread?

Trichomoniasis spreads via unprotected sex. The parasite is transmitted from penis to vagina, vagina to penis or vagina to vagina. It is not transmitted via oral sex, anal sex or kissing, and cannot be caught from toilet seats, towels or cutlery. People without symptoms can still pass the infection on to other people.


The most effective form of prevention is practising safe sex. Always use a condom during intercourse, use a condom on sex toys, avoid sharing sex toys and always wash sex toys after use. Safe sex will also protect against other more serious STDs such as HIV, chlamydia and gonorrhoea. For those already being treated for trichomoniasis, it is important to complete the entire course of antibiotics to prevent any reinfection.

Trichomoniasis complications

If left untreated, trichomoniasis infection can last for months or years and can lead to serious health problems such as pelvic inflammatory disease. Infection with trichomoniasis can increase the risk of spreading or contracting other STDs such as HIV. Trichomoniasis does not cause cervical cancer.

Trichomoniasis and fertility/pregnancy

Unlike other STDs such as chlamydia, trichomoniasis does not affect fertility. In some cases, trichomoniasis infection while pregnant can result in premature birth or low weight babies. It is important to tell your healthcare professional if you are pregnant or might be pregnant if you are being tested for trichomoniasis as this may affect treatment options. As treatment can also affect the taste of breast milk it is also important to mention if you are breastfeeding.


Trichomoniasis is a very common and easily treated STD. Practising safe sex can prevent infection.

Sources: CDC, NHS, Sexwise, Hopkins Medicine

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