We examined early-onset newborn group B streptococcal (GBS) infection among the population of a large obstetric center in western Canada for the contemporary period 1987 to 1992. Attack rates for "definite" (bacteremic) and "presumptive" (urine group B antigen positive with clinical evidence) GBS infections were 0.85 and 0.90 per 1000. Ten GBS-associated stillbirths were recorded. Seven deaths occurred among bacteremic newborns (18.4%). Using definitions of Boyer and Gotoff, 87.2% of all mothers with infected newborns manifested at least one risk factor, and 69.8% of all febrile pregnancies with either definition of infected newborn and 61.9% of a subset of the same with bacteremic offspring had maternal temperature 38 degrees C or higher prior to delivery. For our population, recommendations for universal antepartum GBS screening and intrapartum prophylaxis must be discussed in the context of an existing low frequency of bacteremic disease and with the understanding that fever in pregnancy may be enough to warrant greater intervention that might further reduce the rate of infection.