Objective: To determine the rate of histologic fetoplacental inflammation in fetuses and newborns with fatal perinatal Group B-Streptococcus (GBS) infection.
Study design: Autopsy files (1990 to 2002) were searched for fetuses and newborns with GBS-positive post-mortem blood and/or lung cultures. The rate of histological fetoplacental inflammation in preterm (< 36 weeks gestational age) and term (> or =36 weeks) fetuses/infants was compared using chi(2) test.
Results: GBS infection was diagnosed in 4.9% (61/1236) of perinatal autopsies and was considered the exclusive cause of death in 58 cases (16 to 41 weeks gestation, median: 26 weeks). A total of 43 fetuses/infants (74%) were preterm, 24 (41%) were male and 33 (57%) stillborn. The histologic fetoplacental inflammatory response was age-dependent for the following variables: acute chorioamnionitis (seen in 67% of preterm vs 33% of term fetuses/infants, p < 0.05), multiple-vessel umbilical vasculitis (37 vs 7%, p < 0.05), funisitis (37 vs 13%, p < 0.05), and the presence of neutrophils in the gastrointestinal tract (35% vs none, p < 0.05). Neutrophils in the pulmonary airspaces (47 vs 33%) and pneumonia (16 vs 27%) were found with similar frequency in both groups.
Conclusion: Histologic fetoplacental inflammation is a poor indicator of perinatal GBS infection; the sensitivity is 67% in preterm and 33% in term fetuses/newborns (overall sensitivity 59%). The higher rate of histologic inflammation in preterm fetuses/newborns suggests age-specific interactions between microorganism, host and placenta.