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

Abstract

Objective: Currently, the Centers for Disease Control and Prevention, The American College of Obstetricians and Gynecologists, and the American Academy of Pediatrics recommend that health care providers for pregnant women implement 1 of 2 strategies for the potential prevention of early-onset neonatal group B streptococcal sepsis. Both algorithms recommend intrapartum antibiotic chemoprophylaxis for patients delivered of their neonates at <37 weeks’ gestation. The basic difference lies in the management of the term pregnancy. One protocol suggests treatment of all patients with term pregnancies with a positive culture for group B Streptococcus obtained at 35 to 37 weeks’ gestation. The second approach recommends treatment on the basis of risk factors of membrane rupture of ≥18 hours’ duration or intrapartum temperature of ≥38°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 objective was to prospectively collect every case of blood culture–proven early-onset neonatal group B streptococcal sepsis and determine whether risk factors, 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 completed on December 31, 1996. Every patient that was delivered of a neonate in whom early-onset group B streptococcal sepsis developed was analyzed in detail for possible intrapartum risk factors. Results: A total of 49 cases of early-onset group B streptococcal sepsis occurred in 46,959 deliveries. Of these 49 newborns, 9 (18%) were delivered at <37 weeks’ gestation. The remaining 40 newborns were delivered at term, and only 12 (30%) were delivered with an intrapartum risk factor of either membrane rupture of ≥18 hours’ duration or temperature of ≥38°C or both. Conclusions: On the basis of the data from this study and the current literature, the risk factor approach with the current guideline recommendations would capture <50% of the term newborns in whom sepsis develops. (Am J Obstet Gynecol 1999;181:1243-9.)