Syphilis seroprevalence among pregnant women and its role as a risk factor for stillbirth in Maputo, Mozambique

Objective: To elucidate the role of current syphilis as a risk factor for foetal death. Methods: Sera were obtained from 57 women with third trimester foetal death (cases) and 58 women with foetus alive (controls) matched for age and parity. All sera reactive in qualitative Rapid Plasma Reagin (RPR) analyses were tested with serial twofold dilutions to determine endpoint flocculation titres and tested with the micro-haemagglutination assay for Treponema pallidum (MHA-TP). Placental biopsies were sectioned and stained by haematoxylin-eosin and Warthin-Starry for light microscopy. Setting: Central Hospital, in Maputo, Mozambique, from January 1990 to June 1991. Results: The MHA-TP was reactive in 42% of cases and in 12% of controls (OR = 5.3; 95% CI: 1.9-15.4). The RPR card test was reactive at the dilution of 1:32 or greater in 28% of cases and in 7% of controls. All these results were confirmed by MHA-TP (OR = 5.3; 95% CI: 1.5-15.4). In 9/28 (32%) MHA-TP seroreactive women (7 cases and 2 controls) placental morphological changes indicated syphilitic infection. Conclusion: MHA-TP seroreactivity and high titre RPR were associated with stillbirth. Morphological changes presumptive of syphilis infection were found in 32% placentas histologically studied. Syphilis is a risk factor for foetal death in Maputo, Mozambique.