Randomized study of vaginal chlorhexidine disinfection during labor to prevent vertical transmission of group B streptococci.

OBJECTIVE To evaluate the effect of vaginal disinfection with chlorhexidine gel during labor on vertical transmission of group B streptococcus, as a method to prevent vertical transmission and subsequent neonatal early onset group B streptococcal disease. STUDY DESIGN A prospective study with randomization of 1020 parturients to one of three groups as soon as labor started. In all parturients, anus, introitus and cervix were cultured semiquantitatively. Two groups were treated double-blindly with 10 ml of either a 0.3% chlorhexidine gel or a placebo gel, applicated around the portio and into the fornices. If labor still continued, a second application was given after 10 h. The third group received no treatment. Ear, pharynx and umbilicus of all newborns were also cultured semiquantitatively. RESULTS Nine hundred and eighty one women were evaluated. The overall incidence of group B streptococcal carriership was 19.4%. Vertical transmission was 52.4% in the chlorhexidine group, 71.4% in the placebo group and 66.7% in the control group (P = 0.069). When testing the transmission rates for the chlorhexidine versus the combined placebo plus control group (69.3%), the difference was 16.9% (P = 0.026). CONCLUSION Vaginal disinfection with a chlorhexidine gel during labor modestly reduces group B streptococcal vertical transmission. Because the method is cheap, simple and safe, it should be considered for routine use. Our results indicate that it may reduce the incidence of early onset group B streptococcal sepsis by 2-32%.