title: Elevated second-trimester amniotic fluid interleukin-6 levels predict preterm delivery.
abstract: OBJECTIVE
  Our purpose was to determine whether early second-trimester amniotic fluid interleukin-6 levels predict delivery before 34 weeks' gestation.
  
  
  METHODS
  We used stored second-trimester amniotic fluid samples obtained from women undergoing genetic amniocentesis from 1988 to 1996. Interleukin-6 levels were measured by enzyme-linked immunosorbent assay in samples from every case known to result in delivery from 20 to 34 weeks' gestation (n = 290), and 290 matched controls delivering at > or =37 weeks. Fetal aneuploidies, anomalies, and all cases delivering within 30 days of the amniocentesis (which were thought to be possibly procedure related) were excluded.
  
  
  RESULTS
  Interleukin-6 levels were higher in cases than controls (1.9 +/- 5.2 vs 1.0 +/- 2.4 ng/ml, p = 0.004). Cases were grouped according to whether the preterm delivery was indicated or spontaneous: The mean interleukin-6 levels were significantly higher than controls in the spontaneous group (1.6 +/- 3.2 vs 0.8 +/- 1.2 ng/ml, p = 0.01) but not in the indicated group (1.4 +/- 4.0 vs 0.8 +/- 1.2 ng/ml, p = 0.12). In all samples the interleukin-6 level was negatively correlated with the gestational age at delivery (R = -0.11633, p = 0.007).
  
  
  CONCLUSIONS
  Elevated early second-trimester amniotic fluid interleukin-6 levels are associated with preterm delivery, confirming that in some women this indicator of very early intrauterine inflammation predicts birth before 34 weeks' gestation.
authors.affiliation: Center for Obstetric Research, Department of Obstetrics and Gynecology, The University of Alabama at Birmingham, 35233-7333, USA.
authors.forename: K D
authors.initials: KD
authors.lastname: Wenstrom
authors.forename: W W
authors.initials: WW
authors.lastname: Andrews
authors.forename: J C
authors.initials: JC
authors.lastname: Hauth
authors.forename: R L
authors.initials: RL
authors.lastname: Goldenberg
authors.forename: M B
authors.initials: MB
authors.lastname: DuBard
authors.forename: S P
authors.initials: SP
authors.lastname: Cliver
mesh_terms: D000328:Adult; D000653:Amniotic Fluid / Q000378:metabolism*; D016022:Case-Control Studies; D002821:Chorioamnionitis / Q000150:complications* / Q000175:diagnosis*; D005260:Female; D006801:Humans; D015850:Interleukin-6 / Q000378:metabolism*; D007752:Obstetric Labor, Premature / Q000209:etiology*; D011247:Pregnancy; D011251:Pregnancy Complications, Infectious / Q000175:diagnosis*; D011256:Pregnancy Outcome; D011262:Pregnancy Trimester, Second / Q000378:metabolism*
chemical_list: D015850:Interleukin-6