Untreated trichomoniasis doesn’t just linger quietly. It can cause chronic inflammation that raises your risk of HIV, pelvic inflammatory disease, pregnancy complications, and potentially cervical cancer. About 80% of infections produce no symptoms in either men or women, which means many people carry the parasite for months or years without knowing it, giving these complications time to develop.
Why Asymptomatic Infections Are So Risky
Trichomoniasis is caused by a tiny parasite called Trichomonas vaginalis, and the majority of people who have it feel perfectly fine. With 80% of infections showing no symptoms at all, many people unknowingly pass it to sexual partners and never seek treatment. The infection doesn’t resolve on its own. Without medication, the parasite can survive in the genital tract for months to years, silently triggering low-grade inflammation the entire time.
That persistent inflammation is the root of nearly every complication listed below. It damages the protective lining of the genital tract, creating micro-tears and attracting immune cells to the area in ways that paradoxically make the body more vulnerable to other infections.
Increased Risk of HIV and Other STIs
One of the most serious consequences of untreated trichomoniasis is a 1.5 times greater risk of acquiring HIV. The inflammation caused by the parasite disrupts the mucosal barrier in the vagina or urethra, essentially opening the door for HIV to enter the bloodstream more easily. The same mechanism works in reverse: someone with both trichomoniasis and HIV is more likely to transmit HIV to a partner because the infection increases viral shedding in genital secretions.
This heightened vulnerability isn’t limited to HIV. The inflamed tissue makes it easier to contract other sexually transmitted infections as well, creating a cycle where one untreated infection compounds the risk of another.
Pregnancy and Newborn Complications
Pregnant women with untreated trichomoniasis face meaningfully higher risks of several serious outcomes. A large meta-analysis of the available research found that infected women had about 1.3 times the odds of preterm delivery, nearly twice the odds of premature rupture of membranes (when the water breaks too early), and roughly double the odds of delivering a low birth weight baby, meaning under 5.5 pounds.
Premature rupture of membranes is particularly concerning because it can trigger labor weeks before the baby is ready, raising the chances of respiratory problems and other complications tied to prematurity. While perinatal transmission of the parasite to the baby during delivery is uncommon, it can occasionally cause respiratory or genital infection in the newborn.
Pelvic Inflammatory Disease in Women
In women, untreated trichomoniasis is associated with an increased risk of pelvic inflammatory disease (PID), a condition where infection spreads from the vagina or cervix into the uterus, fallopian tubes, or ovaries. PID can cause chronic pelvic pain, scarring of the reproductive organs, and damage to the fallopian tubes that leads to infertility or increases the risk of ectopic pregnancy. Even mild, repeated bouts of inflammation from a lingering trichomoniasis infection can contribute to this kind of cumulative reproductive damage over time.
Complications in Men
Men tend to get less attention when it comes to trichomoniasis, partly because the infection clears on its own more often in men than in women and partly because symptoms are even rarer. But when the infection persists, it can cause urethritis (inflammation of the urethra that leads to burning during urination or discharge) and may spread to the prostate or epididymis. Epididymitis causes pain and swelling in the testicle, typically on one side, and can become chronic if left untreated.
There’s also evidence linking trichomoniasis to reduced fertility in men. Lab studies have shown that the parasite produces metabolic byproducts that dramatically reduce sperm motility, the ability of sperm to swim effectively toward an egg. For couples struggling with unexplained infertility, an undiagnosed trichomoniasis infection in either partner is worth investigating.
A Possible Link to Cervical Cancer
A growing body of research points to a connection between trichomoniasis and cervical cancer. A systematic review covering nearly 474,000 women found that those infected with the parasite were 1.8 times more likely to also have HPV, the virus responsible for most cervical cancers. More strikingly, trichomoniasis was associated with 2.3 times greater odds of high-grade precancerous cervical changes and over 5 times the odds of cervical cancer itself.
Researchers believe the chronic inflammation caused by the parasite may create an environment where HPV thrives more easily and where damaged cervical cells are more susceptible to cancerous transformation. This doesn’t mean trichomoniasis directly causes cancer, but it appears to significantly amplify the risk when HPV is also present.
Who Should Get Screened
Because so many infections are silent, routine screening is the only reliable way to catch trichomoniasis early. Current CDC guidelines recommend screening for all women living with HIV and suggest it for women in high-prevalence areas or those with risk factors like multiple sexual partners, a history of other STIs, or engagement in transactional sex. Screening can also be considered for anyone living in a county with high trichomoniasis rates.
Testing is straightforward, typically involving a vaginal swab or urine sample, and the infection is curable with a single course of oral antibiotic medication. Both partners need treatment at the same time to prevent passing the parasite back and forth. The simplicity of the cure makes the potential consequences of leaving it untreated all the more avoidable.