title: Maternal serum interleukin-6 during pregnancy and during term and preterm labor.
abstract: OBJECTIVE
  To determine the normal concentrations of maternal serum interleukin-6 during the second and third trimesters of pregnancy and the different stages of term and preterm labor, and to examine the clinical usefulness of measuring this cytokine in the serum of women in preterm labor to diagnose asymptomatic intrauterine infections.
  
  
  METHODS
  Maternal serum interleukin-6 concentrations were measured cross-sectionally in 315 gravidas in their second and third trimesters and during term and preterm labor. Placentas from women who delivered preterm were examined for histologic chorioamnionitis.
  
  
  RESULTS
  At term, women in labor had significantly elevated median maternal serum interleukin-6 concentrations compared with those at term not in labor (4.7 pg/mL versus 2.2 pg/mL, P < .001). Women admitted in preterm labor who delivered had significantly higher median interleukin-6 concentrations than did those in preterm labor who responded to tocolysis (9.3 pg/mL versus 1.9 pg/mL, P < .001). Women in preterm labor who delivered preterm with evidence of chorioamnionitis had significantly higher serum concentrations of interleukin-6 than did those in preterm labor who delivered in the absence of chorioamnionitis (15.9 pg/mL versus 4.6 pg/mL, P = .006).
  
  
  CONCLUSIONS
  Compared with antepartum gravidas, those in term or preterm labor had significantly higher concentrations of maternal serum interleukin-6 concentrations; extremely elevated levels were found in patients whose preterm labor was associated with intrauterine infection.
authors.affiliation: Department of Obstetrics and Gynecology, Duke University Medical Center, Durham, North Carolina, USA. pgreig@gmhms.ghs.org
authors.forename: P C
authors.initials: PC
authors.lastname: Greig
authors.forename: A P
authors.initials: AP
authors.lastname: Murtha
authors.forename: C J
authors.initials: CJ
authors.lastname: Jimmerson
authors.forename: W N
authors.initials: WN
authors.lastname: Herbert
authors.forename: B
authors.initials: B
authors.lastname: Roitman-Johnson
authors.forename: J
authors.initials: J
authors.lastname: Allen
mesh_terms: D005260:Female; D006801:Humans; D015850:Interleukin-6 / Q000097:blood*; D007743:Labor, Obstetric / Q000097:blood*; D007752:Obstetric Labor, Premature / Q000097:blood*; D011237:Predictive Value of Tests; D011247:Pregnancy / Q000097:blood*; D011262:Pregnancy Trimester, Second; D011263:Pregnancy Trimester, Third; D012372:ROC Curve; D012016:Reference Values; D012680:Sensitivity and Specificity
chemical_list: D015850:Interleukin-6