RESUMEN
OBJECTIVE: To determine the risk factors related to group B streptococcal (GBS) colonization in pregnant women on admission in labor MATERIAL AND METHOD: From the 1st-30th October 2004, at the Rajavithi Hospital, 320 pregnant women, who fulfilled the specified criteria, were selected for a cross-sectional descriptive study. Swabs were cultured from the lower vagina and anorectum for GBS using Todd-Hewitt broth with nalidixic acid 15 microg/ml and gentamicin 8 microg/ml only. RESULTS: Colonization was present in 58 cases (18.12%). The risk factor for GBS colonization was an older mean maternal age and a lower mean gestational age. No mothers or neonates during the study period developed a clinical infection from GBS. CONCLUSION: The risk factors for GBS colonization in pregnant women were older maternal age and lower gestational age.