Inflammatory cytokines and antioxidants in midtrimester amniotic fluid: correlation with pregnancy outcome

Am J Obstet Gynecol. 2011 Feb;204(2):155.e1-7. doi: 10.1016/j.ajog.2010.08.064. Epub 2010 Oct 14.


Objective: Elevated interleukin-6 (IL-6) level in midtrimester amniotic fluid is associated with preterm delivery. We hypothesized that, in patients with elevated IL-6, vitamin C and alpha-fetoprotein may provide protection from spontaneous preterm delivery through antioxidant functions.

Study design: Antioxidant potential of alpha-fetoprotein was assessed in vitro. Amniotic fluid was collected from a prospective cohort of patients who underwent midtrimester amniocentesis. In patients with IL-6 >600 pg/mL, alpha-fetoprotein, vitamin C, tumor necrosis factor-alpha, tumor necrosis factor receptors, and antioxidant capacity were compared between subjects with spontaneous preterm and term deliveries.

Results: Alpha-fetoprotein demonstrated 75% the antioxidant capacity of albumin in vitro. Of 388 subjects, 73 women had elevated IL-6 levels. Among these subjects, alpha-fetoprotein, but not vitamin C, was significantly lower in 9 women with preterm birth. Antioxidant capacity correlated with vitamin C and tumor necrosis factor receptors, but not with alpha-fetoprotein or pregnancy outcome.

Conclusion: Amniotic fluid alpha-fetoprotein, but not vitamin C, may protect against preterm birth in patients with elevated midtrimester IL-6 levels.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amniocentesis
  • Amniotic Fluid / chemistry
  • Amniotic Fluid / metabolism*
  • Ascorbic Acid / analysis
  • Ascorbic Acid / metabolism*
  • Female
  • Humans
  • Infant, Newborn
  • Interleukin-6 / analysis
  • Interleukin-6 / metabolism*
  • Linear Models
  • Pregnancy
  • Pregnancy Outcome
  • Pregnancy Trimester, Second / metabolism*
  • alpha-Fetoproteins / analysis
  • alpha-Fetoproteins / metabolism*


  • Interleukin-6
  • alpha-Fetoproteins
  • Ascorbic Acid