A case control study of chorioamniotic infection and histological chorioamnionitis in stillbirth

In order to elucidate the role and aetiology of chorioamnionitis in stillbirth a case referent study was carried out in 58 pregnant women with late foetal death (cases) and in 58 pregnant women at term with live foetus (referents) matched for age and parity in Maputo Mozambique. Samples from women, stillborns and liveborns, were collected for microbiological and histological assessment. Histological chorioamnionitis was diagnosed in 96% of the cases and in 67% of the referents (OR=13.5; 95% CI: 2.9-123.9). Escherichia coli was the species most frequently isolated in stillborns; in 14/16 (88%) cases it was isolated from intracardiac fluid. E. coli was associated with chorioamnionitis in 28% of the stillborns as compared to 5% of the referents (OR=6.9; 95% CI: 1.4-65.4). No group B streptococci were recovered from any placenta or newborn. Vasculitis was present in 12 (21%) cases and in 3 (5%) referents (OR=4.8; 95%, CI: 1.2-27.7). Histological chorioamnionitis was thus associated with stillbirth. E. coli was common in stillborns. The presence of vasculitis in one fifth of the stillborns indicated that the foetus was alive at the onset of infection.