Evidence for fetal involvement in the pathologic process of clinical chorioamnionitis.
OBJECTIVE
Clinical and histologic chorioamnionitis have recently been identified as risk factors for cerebral palsy. Proinflammatory cytokines have been implicated in the mechanisms that are responsible for brain injury in cases of intrauterine infection. The purpose of this study was to determine whether clinical chorioamnionitis, which is a maternal syndrome, is associated with an elevation in the fetal plasma interleukin-6 (IL-6) that is indicative of fetal inflammation.


METHODS
A cross-sectional study was designed to determine plasma concentrations of IL-6 in umbilical venous blood from patients with clinical chorioamnionitis (n = 26) and a control group (n = 111). Umbilical cord blood was obtained at the time of delivery. Plasma concentrations of IL-6 were measured with a sensitive and specific immunoassay. Nonparametric statistics were used for analysis.


RESULTS
Plasma concentrations of IL-6 were detectable in all samples of umbilical venous plasma. The median concentration of plasma IL-6 was higher in neonates born to mothers with clinical chorioamnionitis than in neonates born to mothers in the control group (clinical chorioamnionitis: median, 27.46 pg/mL; range, 1.3-5550.0 pg/mL; vs control: median, 2.13 pg/mL; range, 0.6-812.3 pg/mL; P <.001). Sixty-two percent of neonates (16/26) who were born to women with clinical chorioamnionitis had fetal plasma concentrations of IL-6 >11 pg/mL and 54% (14/26) had fetal plasma concentrations of IL-6 >18 pg/mL (these cutoff points have been used previously to define the fetal inflammatory response syndrome).


CONCLUSIONS
Umbilical vein plasma concentrations of interleukin-6 are elevated in the neonates who were born to mothers with clinical chorioamnionitis, which suggests that the inflammatory process that is responsible for the maternal syndrome of clinical chorioamnionitis frequently involves the human fetus.
Chaiworapongsa
Tinnakorn
T
Perinatology Research Branch, National Institute of Child Health and Human Development, Detroit, MI 48201, USA.
Romero
Roberto
R
Kim
Ju Cheol
JC
Kim
Yeon Mee
YM
Blackwell
Sean C
SC
Yoon
Bo Hyun
BH
Gomez
Ricardo
R
D000293:Adolescent; D000328:Adult; D002821:Chorioamnionitis / Q000503:physiopathology*; D003430:Cross-Sectional Studies; D005260:Female; D005312:Fetal Blood; D005333:Fetus / Q000502:physiology*; D006801:Humans; D007118:Immunoassay; D015850:Interleukin-6 / Q000097:blood*; D009994:Osmolar Concentration; D011247:Pregnancy; D012016:Reference Values; D014680:Veins
D015850:Interleukin-6