Abstract
This study aimed to determine the incidence and clinical outcomes for varying patterns of placental histological inflammation (consistent with fetal or maternal inflammatory response) in an unselected population of >1000 women with a singleton pregnancy resulting in live birth delivering at or near term. One thousand one hundred nineteen cases were studied in a blind, prospective, unselected study with placentas categorized into five histological subgroups reflecting underlying maternal or fetal inflammatory response. Clinical outcomes studied included interventional delivery, an Apgar score <7 at 1 min, neonatal acidosis (pH < 7.2) and admission to neonatal special care. One hundred eighty-eight placentas (17%) showed histological evidence of acute inflammation: 64 with funisitis (with or without other inflammation; 6%); 16 with extensive acute inflammation across the chorionic plate, free membranes and subchorionic fibrin (1%); 28 with acute inflammation restricted to the chorionic plate (2%); 12 with acute inflammation restricted to the free membranes (1%) and 68 with acute inflammation restricted to the subchorionic fibrin (6%). Features of extensive acute inflammation were significantly associated with increased rate of interventional delivery (assisted vaginal delivery or emergency caesarean section; P < 0.01). The presence of funisitis was significantly associated with interventional delivery and other adverse outcomes including an Apgar score <7 at 1 min, clinical evidence of sepsis and admission to the neonatal intensive care unit (P < 0.05 for all). The data represent a quantitative rather than purely qualitative analysis of the contribution of histological lesions related to inflammation on short-term adverse neonatal outcomes and interventional delivery. Funisitis and extensive inflammation are associated with adverse clinical outcomes, but the precise mechanism underlying these remains to be elucidated.