Prenatal screening for group B Streptococcus. I. Impact of antepartum screening on antenatal prophylaxis and intrapartum care.

OBJECTIVE: Our purpose was to evaluate current obstetric practice regarding screening and prophylaxis for group B Streptococcus and to evaluate the impact of screening on antepartum and intrapartum care.

STUDY DESIGN: A total of 1232 members of the Society of Perinatal Obstetricians were asked to indicate their practices regarding screening for group B Streptococcus. Respondents were then asked their practices regarding antepartum and intrapartum prophylaxis on the basis of screening cultures, prior antimicrobial treatment, and other risk factors for neonatal sepsis.

RESULTS: Of the 925 respondents (75.1%), 30.8% performed routine screening in all pregnancies: first prenatal visit (42.3%), 26 to 28 weeks (41.3%), and 34 to 38 weeks (22.1%). In addition, 65.9% would screen patients only under high-risk situations. Although 70.5% sample multiple sites, respondents were inconsistent regarding the sites from which cultures are obtained: distal vagina (64.2%), cervix (53.9%), proximal vagina (40.0%), anal canal (38.5%), and urethra (4.3%). A total of 34.7% of respondents would treat the patient at the time of a positive culture. Knowledge of maternal group B Streptococcus carriage would significantly alter intrapartum prophylaxis in low-risk (60.3% vs 0.5%) and various high-risk populations (74.0% to 98.4% vs 11.3% to 55.0%). However, no consensus as to optimal practice was identified.

CONCLUSIONS: This survey demonstrates significant inconsistencies in screening and prophylaxis for group B Streptococcus by specialists in maternal-fetal medicine. In addition, it reveals that the recommendations of The American College of Obstetricians and Gynecologists and the American Academy of Pediatrics are not routinely followed by these specialists. Knowledge of group B Streptococcus carriage significantly increases antepartum and intrapartum treatment regardless of the presence of other risk factors for neonatal sepsis. The impact of this practice on neonatal therapy warrants further evaluation.