The association of preterm labor with vaginal colonization of group B streptococci

Background: Group B streptococcus is regarded as a potential factor for adverse outcomes of pregnancy such as preterm birth.
Objective: To study the association of maternal vaginal colonization with group B streptococcus (GBS) and preterm labor.
Materials and Methods: From April 2005 to May 2006, vaginal culture for GBS were conducted in 101 laboring women with a gestational age of 24-37 weeks and 105 women admitted for term delivery at maternity center of Afzalipour Hospital in Kerman, Iran. Student's t test and Chi square test were used to compare continuous and categorical data between the groups. Using multivariate logistic regression the association between GBS colonization and preterm labor was analyzed. P-values<0.05 were considered as significant.
Results: Colonization was detected in 9.2% of all mothers. Although GBS colonization was found more frequently in preterm than term patients (12 v/s 7 cases), the difference was not statistically significant. However, GBS positivity was roughly associated with preterm labor. Age was also a risk factor for GBS colonization. No case of perinatal sepsis occurred during the study period.
Conclusion: Maternal colonization for GBS is relatively low in our center. Increasing age enhances the risk of colonization. Vaginal colonization of GBS is relatively associated with preterm labor.