Group B streptococcal infections during pregnancy.

Group B streptococcus, acquired intrapartum from the female genital tract, is the leading cause of neonatal sepsis. Intrapartum maternal antibiotic prophylaxis administered to colonized parturients is efficacious in reducing neonatal colonization and morbidity. However, the optimal method of identifying mother-infant pairs at risk remains controversial. Universal antenatal screening has been effective in identifying colonized women for subsequent intrapartum therapy in research protocols. However, the cost-effectiveness and efficacy of this management scheme, in a general population, has not been determined. The predictive value of antenatal cultures for identifying intrapartum group B streptococcus colonization varies inversely with the interval between culture and delivery with generally low predictive values for cultures performed more than 10 weeks before delivery. Rapid intrapartum screening with various methods has been investigated in a number of studies, while several methods are sensitive in identifying heavily colonized women, they remain insensitive in detecting light colonization.