Maternal inflammation in spontaneous term labor

OBJECTIVE: The purpose of this study was to examine the association between peripheral markers of maternal inflammation and the onset of term labor. STUDY DESIGN: A nested case-control study was performed with serum that had been collected at routine visits from a cohort of 607 term nulliparous women. Cases (n = 20) labored spontaneously within 48 hours of enrollment, and control subjects (n = 80) labored spontaneously >= 14 days after enrollment. Maternal serum cytokines were determined with the use of standard multiplex protocols. Median levels of interleukin-1, -4, -6, -8, and -10, interferon-gamma, and tumor necrosis factor-alpha were compared with the use of the Mann-Whitney U test. Correlations between cytokine levels and maternal factors were performed (Spearman's rho). RESULTS: Median interleukin-1 and -6 and tumor necrosis factor-alpha levels were significantly higher in cases vs control subjects (0.76 vs 0.31 pg/mL [P < .01]; 2.05 vs 0.95 pg/mL [P = .03]; 0.81 vs 0.51 pg/mL [P = .02], respectively). Latency until delivery was inversely correlated with interleukin-1 and tumor necrosis factor-alpha (-0.28 [P < .01]; -0.246 [P < .01]), but not with interleukin-6. CONCLUSION: Maternal proinflammatory markers increase before spontaneous term labor.