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What is trichomoniasis (trich)?

Trichomoniasis is an infection caused by a parasite. It's spread by sexual contact (sexually transmitted infection, or STI). It's sometimes called trich (say "trick"). Anyone can get trich, but most people don't have symptoms. Trich can cause problems during pregnancy.

What causes it?

Trich is caused by a parasite. The parasite usually infects the urethra, bladder, vagina, or cervix.

What are the symptoms?

Most people don't have any symptoms of trich. But if you do have symptoms, they may include:

  • Abnormal discharge from the vagina or penis.
  • Irritation or itching in the genital area.
  • Pain or burning when you urinate.
  • Pain during sex.

How is it diagnosed?

To diagnose trich, your doctor will ask you questions about your symptoms and your sexual history. You may also have a physical exam. This includes a visual exam of your vulva or penis. The doctor will look for patchy red spots that are caused by trich. Any discharge will be checked for colour, odour, and texture.

Several types of tests can be used to diagnose trich. Most use a sample of urine or a swab from the cervix or vagina.

How is trich treated?

Trich is treated with antibiotics such as metronidazole. These medicines kill the parasite that causes the infection. The medicine is usually taken by mouth as pills, tablets, or capsules.

Vaginal creams and suppositories can help ease symptoms, but they won't cure trich.

Your sex partner(s) should be treated at the same time as you are treated. This increases the cure rate and helps prevent you from spreading the disease or getting it again.

Trich during pregnancy raises the risk of prelabour rupture of membranes (PROM) and preterm delivery. Treating the infection may not always reduce this risk. But it can relieve symptoms and prevent infection in the newborn.

It's possible to get trich again. So take steps to reduce your risk for trich and other sexually transmitted infections (STIs).

If symptoms don't go away, you may need to take the medicine again.

How can you prevent sexually transmitted infections (STIs)?

Here are some ways to help prevent STIs.

  • Limit your sex partners. Sex with one partner who has sex only with you can reduce your risk of getting an STI.
  • Talk with your partner or partners about STIs before you have sex. Find out if they are at risk for an STI. Remember that it's possible to have an STI and not know it.
  • Wait to have sex with new partners until you've each been tested.
  • Don't have sex if you have symptoms of an infection or if you are being treated for an STI.
  • Use a condom every time you have sex. Condoms are the only form of birth control that also helps prevent STIs.
  • Don't share sex toys. But if you do share them, use a condom and clean the sex toys between each use.

Vaccines are available for some STIs, such as HPV. Ask your doctor for more information.


Current as of: April 19, 2023

Author: Healthwise Staff
Clinical Review Board
All Healthwise education is reviewed by a team that includes physicians, nurses, advanced practitioners, registered dieticians, and other healthcare professionals.

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