Ureaplasma is a group of tiny bacteria that inhabit the respiratory and urogenital (urinary and reproductive) tract. They are some of the smallest free-living organisms in the world. They’re so tiny that they can’t be seen through a microscope.

Ureaplasma is often a part of the human microbiome, which consists of trillions of tiny cells that live in and on the human body. These tiny organisms help you digest food, fight infections, and maintain reproductive health.

Sometimes typically harmless bacteria overgrow and inflame healthy tissues. This creates a colony of bacteria that can lead to infection.

Ureaplasma species have been linked to a variety of medical problems, including bacterial vaginosis and pregnancy complications. Ureaplasma infections appear to be associated with an increased risk of some problems, but not their direct cause. However, research is inconclusive.

Ureaplasma is typically transmitted through sexual contact. It’s very common among sexually active adults. It can enter the body through the vagina or the urethra.

Ureaplasma can also be passed from mother to child. The infection usually goes away within a few months. It’s rare among children and sexually inactive adults.

People with a weakened immune system have the highest risk of Ureaplasma infection. This includes people who are HIV-positive and people who have had an organ transplant.

Most people with a Ureaplasma infection don’t experience any symptoms. Ureaplasma infection is a possible cause of inflammation in the urethra. This is called urethritis. Both men and women may experience the following symptoms of urethritis:

  • pain during urination
  • burning sensation
  • discharge

Ureaplasma is also a possible cause of bacterial vaginosis. Symptoms can include:

  • watery vaginal discharge
  • unpleasant vaginal odor

Ureaplasma may also increase your risk for other conditions, including:

Doctors studied the presence of Ureaplasma in infertile couples throughout the 1970s and 1980s, but the results were mostly inconclusive. Little research has been done since then.

Ureaplasma does seem to play a role in the risk of preterm delivery. It’s important to understand that Ureaplasma doesn’t cause preterm delivery. It’s only one part of a complex series of events.

Inflammation in the reproductive tissues is a common cause of preterm delivery. Many things can lead to inflammation, including bacterial infections in the amniotic sac, cervix, and vagina. Doctors are investigating Ureaplasma as a possible contributing factor to inflammation.

Ureaplasma species may play a role in the following pregnancy complications:

  • premature rupture of the fetal membrane
  • preterm labor
  • intra-amniotic infection
  • chorioamnionitis
  • funisitis
  • placental invasion
  • low birth weight

The presence of Ureaplasma has also been associated with an increased risk of postpartum endometritis, which is inflammation of the uterus. However, a relationship hasn’t been firmly established.

Most doctors don’t normally test for Ureaplasma. If you’re experiencing symptoms and all other problems have been ruled out, doctors can take a sample to send to a lab. They may use any of the following tests to help diagnose Ureaplasma:

  • cervical swab
  • urine sample
  • endometrial swab
  • an endometrial biopsy

Treatment typically involves a course of antibiotics. The preferred antibiotics for a Ureaplasma infection are azithromycin (Zithromax) or doxycycline (Acticlate, Doryx, Vibra-Tabs). If you don’t respond to treatment, your doctor may prescribe another type of antibiotic called fluoroquinolones.

The only way to prevent a Ureaplasma infection is abstinence. Practicing safe sex will significantly reduce your risk of infection from this and other sexually transmitted diseases (STDs).

Birth control doesn’t prevent STDs. You’ll need to use barrier methods like condoms and dental dams to help prevent infection.

Many people have Ureaplasma as a part of their microbiome. The presence of Ureaplasma shouldn’t be much of a problem unless you’re pregnant.

Doctors haven’t yet agreed whether those who are pregnant should be tested and treated for this type of infection. If you’re worried about any pregnancy complications, talk to your doctor about your options.