Histologic chorioamnionitis at term: implications for the progress of labor and neonatal wellbeing.

Objective: The aim of the present study was to evaluate: i) the rate of histologic chorioamnionitis in relation to the onset of labor and mode of delivery; ii) influence of clinical parameters on the risk of histologic chorioamnionitis in laboring women; iii) neonatal outcome in relation to histologic chorioamnionitis.

Methods: A cohort study was conducted on 395 healthy women at term, with singleton uneventful pregnancy, of which 195 with spontaneous onset of labor and 200 with elective cesarean section. All placentas, collected after delivery, were examined for the diagnosis of histologic chorioamnionitis. Mode of delivery, presence of bacterial infection of placenta and membranes, maternal clinical parameters and neonatal outcome were recorded.

Results: The rate of histologic chorioamnionitis in women with spontaneous onset of labor was significantly higher than in those experiencing elective cesarean section (28.7% vs. 11.5%). Nulliparity and the duration of labor were independent variables associated with acute histologic chorioamnionitis. The presence of histologic chorioamnionitis did not affect neonatal outcome.

Conclusions: The present study showed a highest rate of histological chorionamniositis in women delivering after spontaneous onset of term labor, although the mode of delivery either vaginally or by emergency cesarean section was not influenced by the presence of this pathological condition.