Fusobacterium: anaerobic occult amnionitis and premature labor.

Fusobacterium species are well established pathogens. Before the advent of effective anaerobic antimicrobial therapy, they were associated with prolonged, often fatal courses. Previously, fusobacterium had not been identified as a common perinatal pathogen. Three cases of occult amnionitis due to Fusobacterium are presented. Review of five series of occult amnionitis revealed 23 cases. In seven (30.4%), Fusobacterium was isolated. In 14 (60.8%), an anaerobic species was isolated. The average gestational age of patients from whom anaerobes were grown was 29.0 weeks. Of those that grew no anaerobes, the average gestational age was 32.3 weeks (P less than .05). The overall rate of maternal febrile morbidity was 35%. Fusobacterium accounted for 50% of the febrile cases while accounting for only 30.4% of the total cases.