Maternal Serum Interleukin-6, C-Reactive Protein, and Matrix Metalloproteinase-9 Concentrations as Risk Factors for Preterm Birth <32 Weeks and Adverse Neonatal Outcomes

Elevated concentrations of interleukin-6 (IL-6), C-reactive protein (CRP), and matrix metalloproteinase-9 (MMP-9) in fetal and neonatal compartments have been associated with an increased risk for preterm birth (PTB) and/or neonatal morbidity. The purpose of this study was to determine if the maternal serum concentration of IL-6, CRP, and MMP-9 in women at risk for PTB, who are not in labor and have intact membranes, are associated with an increased risk for PTB 90th percentile). However, there was no significant association after adjustment for GA at randomization and treatment group. Logistic regression analysis for each analyte indicated that high maternal serum concentrations of IL-6 and CRP, but not MMP-9, were associated with an increased risk of IVH (odds ratio OR 4.60, 95% confidence interval CI 1.86 to 10.68; OR 4.07, 95% CI 1.63 to 9.50) after adjusting for GA at randomization and treatment group. Most babies (25/30) had grade I IVH. When GA at delivery was included, elevated IL-6 remained significantly associated with IVH (OR 2.77, 95% CI 1.02 to 7.09). An elevated maternal serum concentration of IL-6 and CRP are risk factors for PTB <32 weeks and subsequent development of neonatal IVH. An elevated maternal serum IL-6 appears to confer additional risk for IVH even after adjusting for GA at delivery.