Antibiotics for bacterial vaginosis or Trichomonas vaginalis in pregnancy: a systematic review

To determine whether antibiotic treatment for bacterial vaginosis or Trichomonas vaginalis during pregnancy decreases the risk of preterm birth and associated adverse outcomes.

Pre-MEDLINE and MEDLINE (1966-2003), EMBASE (1980-2003), and the Cochrane Library were searched using the keywords "bacterial vaginosis", "Trichomonas", "Trichomonas vaginalis", "Trichomonas vaginitis", "Trichomonas infections", "pregnancy", "pregnant", "antibiotics", and "antibiotic prophylaxis".

The search produced 1,888 titles, of which 1,256 abstracts were reviewed further. Of these, 1,217 were ineligible. Inclusion criteria were the following: randomized controlled trials in which antibiotics were compared with no antibiotic or placebo, for women in the second or third trimester of pregnancy with symptomatic or asymptomatic bacterial vaginosis or Trichomonas vaginalis, intact membranes, and not in labor. Exclusion criteria were as follows: published in a language other than English, dropout rate of more than 20% of women in either group, and lack of usable outcomes. Of the 39 papers reviewed in detail, 14 studies were included in the meta-analysis.

One of the authors reviewed titles obtained from the searches, and 2 reviewers independently reviewed the abstracts, excluded those that were ineligible, identified eligible papers, and abstracted the data. For women with bacterial vaginosis, antibiotics reduced the risk of persistent infection but did not reduce the risk of preterm birth or the incidence of associated adverse outcomes for the general population or for any subgroup analyzed. For women with Trichomonas vaginalis, metronidazole reduced the risk of persistent infection but increased the incidence of preterm birth.

Contrary to the conclusions of 3 recent systematic reviews, we found no evidence to support the use of antibiotic treatment for bacterial vaginosis or Trichomonas vaginalis in pregnancy to reduce the risk of preterm birth or its associated morbidities in low- or high-risk women.