Umbilical arteritis and phlebitis mark different stages of the fetal inflammatory response

OBJECTIVE: Funisitis, the inflammation of the umbilical cord determined by histologic examination of the placenta, is evidence of a fetal inflammatory response. The inflammatory process may involve the umbilical vein (phlebit is) and one or both umbilical arteries (arteritis) and extend into the Whar ton's jelly. This study was conducted to examine whether the pattern of inf lammation of the umbilical cord correlates with a biochemical marker of sys temic fetal inflammation (umbilical cord plasma interleukin-6) and an adver se neonatal outcome. STUDY DESIGN: This cohort study included 636 cases of preterm delivery (< 3 6 weeks) with or without inflammation of the umbilical cord. Umbilical cord blood was collected at the time of delivery. The aim of pathologic examina tion was to characterize the extent of umbilical cord inflammation and the involvement of the vein (phlebitis), the involvement of one or both arterie s (arteritis), and the presence of inflammation of the Wharton's jelly. Umb ilical cord plasma interleukin-6 concentrations were assayed by a sensitive and specific immunoassay. RESULTS: Neonates with umbilical arteritis had a significantly higher media n concentration of cord plasma interleukin-6 (median, 111 pg/mL; range, 0.1 -19,230 pg/mL) than those without umbilical arteritis (median, 22.5 pg/mL; range, 0.9-511.6 pg/mL; P < .05). Also, severe neonatal morbidity occurred more frequently in infants with arteritis than in those without arteritis ( 74% vs 50%; P < .05). And finally, the most severe form of inflammation, wh ich involves both arteries, vein, and Wharton's jelly, was associated with the highest median concentration of plasma interleukin-6 observed in this s tudy (median, 182.6 pg/mL; range, 0.1-7,400 pg/mL), whereas inflammation li mited to the vein (phlebitis) was associated with a lower concentration of cord plasma interleukin-6 (median, 29.1 pg/mL; range, 0.9-511.6 pg/mL; P < .05). CONCLUSION: Neonates whose placenta demonstrates umbilical arteritis have h igher concentrations of umbilical cord plasma interleukin-6 and higher rate s of adverse outcome than those without umbilical arteritis.