Prenatal Group B Streptococcus Test Using Real-Time Polymerase Chain Reaction

SummaryObjectiveThe aim of this study was to evaluate the percentage of pregnant women with negative Group B Streptococcus (GBS) screening results by culture at 35 weeks' gestation, who subsequently had positive GBS test results after 39 weeks' gestation.Materials and MethodsFrom 2006 to 2007, we recruited 150 pregnant women who received routine GBS culture screening at 35 weeks' gestation with negative results, and who had repeat cultures and real-time polymerase chain reaction (RT-PCR) tests for GBS after 39 weeks' gestation.ResultsTwo percent of pregnant women with GBS-negative results by culture screening at 35 weeks' gestation were GBS-positive at 39 weeks' gestation.ConclusionIt is necessary to perform a GBS test 4 weeks after an initial negative GBS culture at 35–37 weeks of gestation. RT-PCR provides a simple and rapid alternative method for detecting rectovaginal GBS colonization at the time of labor.