Histological chorioamnionitis in relation to clinical presentation at 14-40 weeks of gestation.

This study examines the prevalence of histological inflammation of the fetal membranes according to gestational age and mode of clinical presentation in a series of 179 consecutive placentas evaluated in a single centre. The frequency of histological inflammation between clinical groups was compared and relation between the prevalence of inflammation and gestational age examined using regression analysis. One hundred and seventy-nine placentas were examined. Histological inflammation was present in 65 (38%) cases including 37/52 (71%) pregnancies presenting with spontaneous preterm labour and delivery (PTL), 23/36 (64%) with preterm prelabour rupture of membranes (PPROM), 1/20 (5%) with vaginal bleeding but no contractions (PVB), 1/13 (8%) with intrauterine death but no labour (IUD), 1/28 (4%) with iatrogenic delivery, 0/4 with termination of pregnancy and 2/20 (10%) delivering spontaneously at term. The prevalence of histological inflammation was significantly higher in those with PTL or PPROM compared to the other groups (P<0.0001). The frequency of histological inflammation was associated with gestational age (F=57.2, P<0.0001, R=0.91), with a peak prevalence (>90%) at 20-24 weeks' gestation.