Sixteen RCTs (n=11,412) were included in the review.
Group B Streptococci (1 RCT, n=938): no statistically significant difference was found in the likelihood of a low birth weight (OR 1.43, 95% CI: 0.86, 2.37), pre-term delivery (OR 0.91, 95% CI: 0.61, 1.36) or pre-term PROM (OR 1.0, 95% CI: 0.46, 2.11).
Chlamydia trachomatis (1 RCT, n=414): no statistically significant difference was found in the likelihood of a low birth weight (OR 0.74, 95% CI: 0.38, 1.45), pre-term delivery (OR 0.89, 95% CI: 0.49, 1.62) or pre-term PROM (OR 0.70, 95% CI: 0.19, 2.49).
Ureaplasma urealyticum (1 RCT, n=1,181): no statistically significant difference was found in the likelihood of a low birth weight (OR 1.36, 95% CI: 0.85, 2.17) or pre-term delivery (OR 1.02, 95% CI: 0.67, 1.54).
Trichomonas vaginalis (2 RCTs, n=2,469): there was an increased likelihood of a low birth weight (OR 1.68, 95% CI: 1.11, 2.53) and pre-term birth (OR 1.71, 95% CI: 1.19, 2.46). There was no evidence of statistical heterogeneity for either outcome.
One RCT found no statistically significant difference in the likelihood of pre-term PROM (OR 1.1, 95% CI: 0.5, 2.3).
Bacterial vaginosis (11 RCTs, n=6,410): no statistically significant difference was found in the likelihood of a low birth weight (OR 0.92, 95% CI: 0.60, 1.40), pre-term birth (OR 0.89, 95% CI: 0.66, 1.20) or pre-term PROM (OR 0.77, 95% CI: 0.33, 1.81); these results were based on 6, 11 and 5 studies, respectively. There was evidence of statistical heterogeneity in all of the analyses.
The subgroup analyses on antibiotic use, route of administration, and obstetrical history did not impact on the outcomes for bacterial vaginosis.