Is antenatal group B streptococcal carriage a predictor of adverse obstetric outcome?

Abstract

Objectives While early‐onset neonatal GBS sepsis is positively associated with premature birth and prolonged rupture of membranes, there is debate in the literature as to whether maternal GBS colonization is a predictor of adverse obstetric outcome. This is a critical issue to resolve for appropriate management (expectant vs. interventional management) of the patient presenting with premature rupture of membranes, who has no overt signs of sepsis, but who is colonized with GBS. Methods Since 1981 it has been hospital policy to screen all public patients antenatally for genital carriage of GBS by collection of a low vaginal swab at 28–32 weeks. All patients colonized with GBS antenatally are given penicillin as intrapartum chemoprophylaxis. Review of all GBS‐colonized antenatal patients for a 12‐month period (580 of 4,495 patients) and a randomized (every fourth consecutive antenatal patient) number of noncolonized patients (958) was made. Lower vaginal GBS colonization and other risk factors for preterm delivery were assessed using univariate and multivariate generalized linear modeling. Results In the study group, the maternal GBS colonization rate was 12.9%. When cofounding variables were controlled in a multivariate analysis, the association between antepartum GBS colonization and preterm labor and preterm rupture of membranes was not significant. Conclusion Maternal antenatal carriage of GBS does not predict preterm labor. Therefore it is appropriate that expectant management occur for a GBS‐colonized woman who ruptures her membranes, is not in labor, and has no evidence of sepsis. Infect. Dis. Obstet. Gynecol. 8:138–142, 2000. © 2000 Wiley‐Liss, Inc.

Group B streptococcal carriage in Sweden: a national study on risk factors for mother and infant colonisation

“…This fact has generated several studies aimed at elucidating whether GBS carriage per se is a harbinger of obstetric risk factors that are associated with the emergence of neonatal GBS infection. The extensive study by Regan et al (22) demonstrating an increased risk for the occurrence of preterm birth and preterm prolonged ROM in GBS carriers has been corroborated (23), (24), and contradicted (25), (26). In the present study, we found no association between maternal GBS colonisation and preterm birth or prolonged ROM.…”

Likelihood ratios for the prediction of preterm delivery with biomarkers

“…Bacterial vaginosis diagnosed according to Nugent's criteria provided an LR+ of 1.6 (20) (number of screen‐positive PTD >100), and vaginal carriage of group B streptococci was not associated with PTD (21) (number of screen‐positive PTD 50–100). Based on one small study, the finding of Ureaplasma urealyticum in amniotic fluid had an LR+ of 10.…”

The Prevalence of Vaginal Microorganisms in Pregnant Women with Preterm Labor and Preterm Birth

“…Garland et al [27] reported that GBS is considered a risk factor for S-PTB because of its association with asymptomatic bacteriuria. However, when it colonizes the lower genital tract alone, it is not thought to promote preterm delivery.…”