Group B streptococci cultured in urine during pregnancy associated with preterm delivery: a selection problem?

AbstractObjective: To investigate an association between Group B streptococci (GBS) in urine culture during pregnancy and preterm delivery.Methods: A population-based cohort consisted of all the pregnant women (n = 36,097) from the catchment area of Lillebaelt Hospital, Denmark, during the period January 2002 –December 2012. The cohort of 34,285 singleton pregnancies used in this study was divided into three groups. Group I (N = 249) included women whose urine culture was positive for GBS; group II (N = 5765) included women whose urine culture was negative for GBS; and group III (N = 28 271) included women whose urine had not been cultured during pregnancy. Primary outcome was preterm delivery before 37 weeks’ gestation (PTD).Results: We did not find an association between PTD and GBS bacteriuria in the cultured groups (odds ratios (OR) = 0.89; 95% CI: 0.5–1.4) (Table 1). After controlling for potential confounders, the PTD remained not associated with GBS bacteriuria (adjusted OR = 0.99; 95% CI: 0.6–1.6)...