The capture rate of at-risk term newborns for early-onset group B streptococcal sepsis determined by a risk factor approach

OBJECTIVE: Currently, the Centers for Disease Control and Prevention, The A merican College of Obstetricians and Gynecologists, and the American Academ y of Pediatrics recommend that health care providers for pregnant women imp lement 1 of 2 strategies for the potential prevention of early-onset neonat al group B streptococcal sepsis. Both algorithms recommend intrapartum anti biotic chemoprophylaxis for patients delivered of their neonates at <37 wee ks' gestation. The basic difference lies in the management of the term preg nancy. One protocol suggests treatment of all patients with term pregnancie s with a positive culture for group B Streptococcus obtained at 35 to 37 we eks' gestation. The second approach recommends treatment on the basis of ri sk factors of membrane rupture of greater than or equal to 18 hours' durati on or intrapartum temperature of greater than or equal to 38 degrees C. The capture rate of at-risk neonates determined by the risk factor strategy is quoted as being approximately 70%; however, the basis for this percentage was from studies that used slightly different definitions than the current guidelines and never separated the term from the preterm newborn. Our objec tive was to prospectively collect every case of blood culture-proven early- onset neonatal group B streptococcal sepsis and determine whether risk fact ors, as currently defined, were present that might have warranted maternal intrapartum antibiotic chemoprophylaxis. STUDY DESIGN: A prospective study was initiated on July 1, 1987, and comple ted on December 31, 1996. Every patient that was delivered of a neonate in whom early-onset group B streptococcal sepsis developed was analyzed in det ail for possible intrapartum risk factors. RESULTS: A total of 49 cases of early-onset group B streptococcal sepsis oc curred in 46,959 deliveries. Of these 49 newborns, 9 (18%) were delivered a t <37 weeks' gestation. The remaining 40 newborns were delivered at term, a nd only 12 (30%) were delivered with an intrapartum risk factor of either m embrane rupture of greater than or equal to 18 hours' duration or temperatu re of greater than or equal to 38 degrees C or both. CONCLUSIONS: On the basis of the data from this study and the current liter ature, the risk factor approach with the current guideline recommendations would capture <50% of the term newborns in whom sepsis develops.