Correlation of midtrimester amniotic fluid cytokine concentrations with adverse pregnancy outcome in terms of spontaneous abortion, preterm birth, and preeclampsia

Objective: To assess midtrimester amniotic fluid concentrations of three major proinflammatory cytokines (IL-6, IL-8, and TNF-alpha) in asymptomatic pregnancies with adverse outcomes. Methods: A prospective follow up study at the Charite University Hospital, Berlin, Germany of women with uncomplicated singleton pregnancies at second trimester and amniocentesis. Concentrations of IL-6, IL-8, and TNF-alpha were measured by enzyme-linked immunosorbent assay following amniotic fluid assessment by midtrimester amniocentesis performed from gestation days 15 weeks 0 days up to 20 weeks 6 days. Values from normal pregnancies were compared to those from pregnancies having adverse outcomes of spontaneous abortion, preterm delivery, preeclampsia, or eclampsia. Main outcome measure IL-6, IL-8 and TNF-alpha in relation to adverse pregnancy outcome. Results: A total of 298 consecutive patients were evaluated. Median patient age was 35 years (range 19-43). Controls consisted of 273 women who delivered without further complications after 37 weeks gestation. The range values of IL-6, IL-8, and TNF-alpha in the control group were 4.9-2620 pg/mL, 36.2-5843 pg/mL, and 8.0-28.2 pg/mL, respectively. Patients with adverse pregnancy outcome (n = 25) were classified into three groups: spontaneous abortion group (n = 4), preterm delivery group (n = 17), and preeclampsia/eclampsia group (n = 4). There were no significant differences in IL-6, IL-8, and TNF-alpha between controls and study groups, regardless of the type of complication (p > 0.05). Conclusion: Midtrimester amniotic fluid concentrations of the proinflammatory cytokines IL-6, IL-8, and TNF-alpha are not predictive of adverse pregnancy outcome in terms of spontaneous abortion, preterm delivery or preeclampsia/ eclampsia in our study population.