Ok, this is interesting. I will just speak from my experience about this. I was found to have a similar sexually transmitted bacteria called Ureaplasma Urealyticum... which is a type of Mycoplasma and both can "cause preterm labor or miscarriage." I was about 5-6 weeks pregnant and found out from my fertility doctor. She suggested I go on antibiotics-- Doxycycline to be specific. I did tons of research on this bacteria, because I know that it was risky to take the Doxy while pregnant, it is not certain to be safe and I didn't want to risk harming my baby. Many other who I consulted-- doctors, my current ob/gyn, other specialists... said that the research is extremely lacking and inconclusive that the presence of this bacteria alone causes preterm labor or complications. Most doctors do not even test for it, and they say 70% of sexually active women carry this bacteria in their vaginal tract. Sometimes it can be detected in the cervical culture, sometimes it can't. Now I will say, when you are symptomless I don't believe it causes harm... BUT if you notice symptoms of infections or if it is accompanied by bacterial vaginosis (which you would know, you would have yellow or green smelly discharge) than that is when I think it can potentially cause problems. That is when you know the bacteria has probably run rampant.
The fertility doctor I saw, although she wanted to treat the Ureaplasma, after speaking with her at length about what to do, she reassured me that it is just a precaution and standard procedure for her recurrent miscarriage patients. She didn't believe my previous m/c had anything to do with the bacteria, because it was a missed miscarriage... when this bacteria causes miscarriage it causes bleeding... or if you're further along, infection in the placenta or placental abruption. But she even believed if there is really a risk of preterm labor when you have this bacteria, it is very small.
If you're on antibiotics that should have taken care of the problem. Unless you have a chronic/widespread problem with this bacteria. If this bacteria was rampant in your body, you'd have a host of symptoms that you would definitely know about. I just hope they put you on the right antibiotic too.
Will you be retested to see if the bacteria is gone?