Study	Reason for exclusion
Gjerdingen 2000	Participants did not meet inclusion criteria. Study compared standard prenatal care including routine inquiry about vaginal symptoms versus standard care supplemented by vaginal pH testing. Both arms had pregnant women who were diagnosed with lower genital tract infection and all participants received vaginal pH screening. Participants: 121 pregnant women with or without vaginal infection symptoms. Intervention: vaginal pH testing. Outcomes: bacterial vaginosis detection rate, preterm deliveries.
Gupta 2013	Participants did not meet inclusion criteria. Study compared screening for and treatment of abnormal vaginal flora versus no treatment. Participants: 242 pregnant women with abnormal vaginal flora. Intervention: screening by vaginal swab for Gram stained and examined for budding yeast cells, pseudohyphae and bacteria of various morphotypes, and scored using the Nugent criteria. Outcomes: preterm birth.
McGregor 1995	Methods not clearly described, but seems likely that this was not a randomised controlled trial. Described as a prospective observational trial. Participants: 1260 women. Intervention: lower genital tract micro‐organism screening (vaginal fluid enzyme; nonspecific protease, sialidase, phospholipase C, phospholipase A2). Outcomes: preterm birth, early pregnancy loss.
Sungkar 2012	Participants did not meet inclusion criteria. Study compared self‐examination of vaginal acidity, and microbiologic testing for BV (Gram staining) versus usual prenatal care standard care. Participants: 176 singleton pregnant women with or without vaginal infection symptoms. Intervention: education about preterm birth and its risk factors, self‐examination of vaginal acidity, and microbiologic testing for BV (Gram staining). Outcomes: preterm birth.