Predictive value of serum interleukin-6 and -8 levels in preterm labor or rupture of the membranes

BACKGROUND: The aim of this prospective study was to examine if serum concentrations of cytokines are of value in the identification of patients at risk for preterm delivery. METHODS: Interleukin- 1beta,2,4,6,8 and tumor necrosis factor alpha were determined between 25 and 37 weeks of gestation in the serum of 72 consecutive patients with preterm labor, 38 patients with preterm rupture of the membranes, and 24 healthy pregnant women as a control group. Material was collected within 18 hours after hospitalization and was immediately centrifuged and shock frozen. RESULTS: Significantly increased serum levels were found for interleukin-6 and -8 in patients with preterm labor or preterm rupture of the membranes when compared to the control group (p<0.001 and p<0.005, respectively). In patients with preterm rupture of the membranes and interleukin-6 levels above the median of 4.0 pg/ml the delivery occurred significantly earlier than in patients with lower levels (1 versus 5.5 days; p=0.005). Patients of both pathology groups with detectable (>18 pg/ml). Interleukin-8 levels had a shorter pregnancy duration when compared to other patients (p=0.05 for preterm labor and p=0.04 for preterm rupture of the membranes). Interleukin-1beta,2,4, and tumor necrosis factor alpha were not correlated with clinical outcome. CONCLUSIONS: Increased serum interleukin-6 and -8 levels are associated with a shorter interval between onset of preterm rupture of the membranes and delivery and should therefore be further evaluated for their use in clinical practice.