Maternal serum cytokines in preterm premature rupture of membranes

OBJECTIVE: To estimate whether maternal serum interleukin (IL)-6 or granulocyte colony-stimulating factor (G-CSF) obtained daily are elevated in women with preterm premature rupture of membranes who develop funisitis. METHODS: Daily blood samples were obtained from women with preterm premature rupture of membranes and analyzed for IL-6 and G-CSF by enzyme-linked immunosorbent assay. Funisitis was determined by placental examination. Observations were stratified based on the presence or absence of funisitis and analyzed. Proportional hazards models were used to evaluate time-to-delivery on the basis of diagnostic IL-6 and G-CSF levels, determined by receiver operating characteristic curve analysis. RESULTS: Of the 107 patients available for analysis, 54 (50%) had evidence of funisitis after delivery. Patients with funisitis were more likely to deliver at an earlier gestational age (28.5 weeks compared with 31.5 weeks, P <.001) and have Medicaid insurance (57% compared with 39%, P=.04). Serum IL-6 and G-CSF were elevated 24 to 48 hours before delivery in women with preterm premature rupture of membranes with funisitis compared with those without funisitis (IL-6, 7.5 compared with 2.8 pg/mL, P <.001; G-CSF, 121.7 compared with 56.9 pg/mL, P=.002). Using values identified by the receiver operating characteristic curve, elevated serum IL-6 in the interval 24-72 hours before delivery was significantly associated with funisitis (P <.03), even after controlling for gestational age and insurance status. CONCLUSION: Maternal serum IL-6 and G-CSF appear to be biomarkers in the identification of women with preterm premature rupture of membranes likely to develop funisitis.