Vaginal progesterone is associated with decreased group B streptococcus colonisation at term: a retrospective cohort study

OBJECTIVE To investigate whether women using intravaginal progesterone suppositories for preterm birth prevention during pregnancy will have lower rates of group B streptococcus (GBS) colonisation at term, compared with women receiving intramuscular 17-alpha-hydroxyprogesterone caproate. DESIGN This was a retrospective observational cohort study of women who were prescribed a progestogen during their pregnancy for preterm birth prevention, and who delivered at term. SETTING A tertiary referral hospital in central Ohio. POPULATION Patients who were prescribed a progestogen during their pregnancy for preterm birth prevention between 2004 and 2017 were included in the study. Patients who delivered at