Sexual transmission
Vaginal, anal and oral sex can all transmit Ureaplasma species. Prevalence rises steeply with number of lifetime sexual partners[6][10]. Because carriage is so common in the general population, exposure does not require a "high-risk" partner — a long-term monogamous partner who was never tested can be the source.
Condoms reduce but do not eliminate risk. Skin-to-mucosa contact and shared genital fluids both contribute, and asymptomatic shedding is the rule rather than the exception[4].
Vertical transmission (mother → baby)
Ureaplasma can pass from a colonised mother to the baby in two ways[2]:
- In utero, by ascending from the lower genital tract into the amniotic fluid — the route most strongly linked to chorioamnionitis and preterm birth[3].
- At delivery, as the baby passes through a colonised birth canal. Colonisation rates of 20–55% have been reported in newborns of carrier mothers[1].
(Preconception testing is a recognised strategy in couples with prior pregnancy loss or preterm birth[7].)
What does NOT seem to transmit Ureaplasma
- Toilet seats, doorknobs, swimming pools — these are not credible routes.
- Casual social contact (hugs, handshakes, sharing food).
- Insect bites.
Ureaplasma is fragile outside the human body and does not survive long on surfaces[6].
What reduces risk
- Consistent condom use, especially with new or untested partners.
- Both partners being tested before unprotected sex or conception attempts.
- Treating both partners when one tests positive, to avoid the "ping-pong" effect.
- Routine screening when planning pregnancy, particularly with a history of preterm birth, miscarriage or unexplained infertility[4].