Ja. Keelan et al., Cytokine abundance in placental tissues: Evidence of inflammatory activation in gestational membranes with term and preterm parturition, AM J OBST G, 181(6), 1999, pp. 1530-1536
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.