Eligible studies were randomised controlled trials (RCTs). Inclusion criteria for participants, interventions, and outcomes were not specifically reported, but search terms indicated that the intervention was Lactobacillus-containing probiotics and outcomes were bacterial urogenital infections. The inclusion criteria for the individual trials were provided in tables.
In the included trials, participants were mostly premenopausal with either clinical confirmation of BV diagnosis (by Nugent score or Amsel criteria) or history or signs and symptoms of UTI. Some participants were in their first trimester of pregnancy. Many were required to have no evidence of other infections such as sexually transmitted diseases and in many trials, previous medications, likely to affect the results, were not permitted. Different types of Lactobacillus were administered either as oral capsules, drinks or yoghurt, or in vaginal suppositories, tampons or douches. Treatment durations varied and trial controls were active, placebo, or no treatment. Outcomes included either clinical cure of BV, reduction of recurrent episodes or symptom resolution of BV, or reduction in symptomatic UTI.
The authors did not state how the papers were selected for review nor how many reviewers performed the selection.