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How long can a woman have trichomoniasis without knowing?

Trichomoniasis is a common sexually transmitted infection caused by the parasite Trichomonas vaginalis. It is spread through sexual contact and affects both women and men, but symptoms are more common in women. Many women with trichomoniasis do not have symptoms and can carry the infection for long periods of time without knowing. Detecting trichomoniasis can be challenging since testing is not routinely performed during STD screenings. However, it is important for sexually active women to understand the risks, symptoms, testing options, and treatment for trichomoniasis.

Symptoms of Trichomoniasis

Many women with trichomoniasis do not experience any symptoms. When symptoms do occur, they may include:

  • Yellow, green, or gray vaginal discharge
  • Vaginal odor
  • Vaginal itching or irritation
  • Painful urination
  • Discomfort during intercourse
  • Lower abdominal pain

Some women may also experience spotting between periods if trich is causing inflammation in the vagina. The CDC estimates that only about 30% of people with trichomoniasis develop symptoms.

How Long Can Trichomoniasis Go Undetected?

Trichomoniasis can go undetected for months or even years in women who do not develop symptoms. Studies have found:

  • Up to 70% of women with trich do not have symptoms
  • The parasite can survive inside the vagina and infect new sexual partners for months or years
  • Some women can carry trich infections for over 5 years without treatment

The longest reported duration of untreated trichomoniasis is 18 years in a woman who never developed symptoms. However, most cases of asymptomatic trich are thought to resolve within 6 months to 1 year as the immune system fights the infection. Prompt testing and treatment is still important though, as chronic infections over 6 months increase the risk of pelvic inflammatory disease.

Risk Factors

Certain women are at higher risk of acquiring trichomoniasis and not knowing it. Risk factors include:

  • Having a new sexual partner
  • Having multiple sexual partners
  • Previous STD infection
  • Lack of condom use
  • Douching
  • Smoking
  • History of incarceration
  • Drug use

Women who have these risk factors should consider getting tested for trichomoniasis even if they don’t have symptoms.

Should Trichomoniasis Be Routinely Screened For?

Most doctors do not routinely test women for trichomoniasis during annual exams or STD screenings. This is partly why so many women have trich infections for long periods without detection.

Some organizations like the CDC recommend screening women with the following criteria:

  • Pregnant women
  • Women living with HIV
  • Women with multiple sexual partners
  • Women with a new sex partner in the past 3 months
  • Women with a history of STDs
  • Women requesting an STD check

However, some experts argue that all sexually active women under 35 should be screened for trich annually. This approach would detect more cases and prevent complications. More research is still needed to establish definitive screening recommendations.

Testing Options

Trichomoniasis is typically diagnosed through examination of vaginal secretions:

  • Microscopy: Viewing a wet mount of vaginal discharge under a microscope. This allows direct visualization of trichomonads.
  • Culture: Taking a vaginal swab and incubating it in a special culture medium to grow trichomonads.
  • Nucleic acid amplification tests (NAAT): Detecting trichomonad DNA from a vaginal swab using PCR tests.

NAAT tests are the most sensitive, able to detect 70-90% of trich cases. But access to NAAT testing is still limited, so microscopy or culture may be used for screening. Multiple types of samples may be needed since discharge can be intermittent.

Test Description Sensitivity
Wet mount microscopy Examination of discharge under a microscope 60-70% sensitive
Culture Incubation of discharge to grow trichomonads 85-95% sensitive
NAAT Amplification of trich DNA via PCR 70-90% sensitive

NAAT or nucleic acid amplification tests offer the highest sensitivity but may not be readily available. Multiple testing methods may be needed to increase detection rates.


Trichomoniasis is treated with prescription anti-parasitic medications:

  • Metronidazole: The standard treatment is a single 2 g oral dose of metronidazole. Cure rates exceed 95% with one dose.
  • Tinidazole: Another FDA-approved option with similar efficacy to metronidazole. It is taken as a single 2 g oral dose.

Sexual partners should also be treated to prevent reinfection. Women should avoid sex until treatment is complete and symptoms resolve. Follow up testing is recommended after 3 months to confirm the infection has cleared.

Complications of Untreated Trichomoniasis

Allowing trichomoniasis to persist for years without treatment can lead to complications:

  • Pelvic inflammatory disease (PID): Up to 20% of women with untreated trich develop PID, an infection of the uterus and ovaries.
  • Infertility: PID can scar the fallopian tubes, increasing the risk of infertility if left untreated.
  • Higher risk of HIV: Trich infection causes genital inflammation that facilitates HIV transmission.
  • Preterm birth: Pregnant women with trich are at risk of premature rupture of membranes and early delivery.

Treating trichomoniasis promptly reduces these complications. Women of reproductive age should be aware of trich symptoms and request testing if concerned.

Prevention Tips

Here are some tips for women to reduce their risk of acquiring trichomoniasis:

  • Use condoms correctly every time you have sex
  • Limit the number of sexual partners
  • Ask partners to get tested before unprotected sex
  • Get regular STD screening if sexually active
  • Don’t douche, which can alter vaginal pH
  • Avoid douching with disinfectants
  • Finish your treatment and avoid sex until symptoms resolve


Trichomoniasis often goes undetected for months or years in women without symptoms. An estimated 70% of infections produce no symptoms. Prompt testing and treatment in at-risk women can prevent complications like PID, infertility, and preterm birth. Women should discuss trichomonas screening with their doctor if they are sexually active. All partners must be treated simultaneously to avoid reinfection. With appropriate screening and prevention methods, the incidence of trichomoniasis could be reduced.