Cytokine abundance in placental tissues: Evidence of inflammatory activation in gestational membranes with term and preterm parturition

OBJECTIVES: This study of the changes in cytokine concentrations in gestati onal tissues from women with term and preterm labor was undertaken to asses s the extent of inflammatory activation associated with spontaneous labor a nd delivery. STUDY DESIGN: Extracts of amniotic, chorionic-decidual, and placental tissu es from women delivered at term before labor (n = 15), at term after labor (n = 15), and preterm (n = 31) were assayed for interleukin 1 beta, interle ukin 6, and interleukin 8. RESULTS: In amniotic tissues of women delivered by spontaneous labor at ter m the median interleukin-6, interleukin-8, and interleukin-1 beta concentra tions were 3.8 to 5.4 times those of tissues from women delivered at term w ithout labor (P < .05, Mann-Whitney U test). Interleukin-6 and interleukin- 8 concentrations were also significantly increased (3.3-4 times) in chorion ic-decidual tissues, Marked increases (approximately 3-6 times) in the conc entrations of all 3 cytokines were observed in both amniotic and chorionic- decidual tissues from women with preterm deliveries with respect to those f rom women with term deliveries after labor. Cytokine concentrations were si gnificantly correlated within amniotic tissues from both women with term de livery after labor and women with preterm delivery and also in preterm chor ionic-decidual tissues but not preterm placental tissues. Concentrations of cytokines in the tissues of women delivered preterm were not significantly affected by mode of delivery, treatment with antibiotics, or twin birth. I n preterm tissues with evidence of intrauterine infection only amniotic int erleukin-1 beta concentrations were significantly elevated (P < .05). Littl e or no labor-related change in cytokine concentrations was seen within pla cental tissues. CONCLUSIONS: Increased cytokine abundance in gestational membranes associat ed with labor supports the view that an inflammatory process is involved in both term and preterm labor. This process does not, however, appear to be evident in the villous placenta.