Association between colonization with group B streptococci during pregnancy and preterm delivery among Danish women

OBJECTIVE: We studied the relationship between group B streptococcal coloni zation and preterm delivery. STUDY DESIGN: In this prospective study at a single hospital in Odense, Den mark, cervicovaginal cultures were obtained at less than or equal to 24 wee ks' gestation from all the women, at delivery from women with preterm deliv eries, and from a random sample of women delivering at term. RESULTS: In 2846 singleton births. there was no significant association bet ween group B streptococcal colonization at less than or equal to 24 weeks' gestation and preterm birth. After adjustment for the risk factors for pret erm delivery, more women with preterm delivery (12/84, 14%) were colonized at delivery with group 8 streptococci than women with term deliveries (22/3 00, 7%; adjusted odds ratio, 3.0; 95% confidence interval, 1.4-6.8). Group B streptococcal colonization at less than or equal to 24 weeks' gestation a nd at delivery was significantly less likely to occur in the presence of no rmal vaginal flora. CONCLUSION: Group B streptococcal colonization at delivery, but not at less than or equal to 24 weeks' gestation, was associated with preterm delivery .