Elevated maternal serum IL-6 and CRP are associated with preterm delivery

Abstract

To determine if there is an association between maternal serum concentrations of C-reactive protein (CRP), Interleukin-6 (IL-6), and Matrix Metalloproteinase-9 (MMP-9), preterm birth <32 weeks, and subsequent neonatal intraventricular hemorrhage. These analytes were chosen because they are markers for the “acute phase response”. Analysis of 443 patients enrolled in a multicenter randomized controlled trial of single versus weekly corticosteroids for women at increased risk for preterm delivery for whom serum was collected at randomization (24-32 weeks gestation). CRP, IL-6, and MMP-9 were subsequently measured by sensitive and specific immunoassays. Multivariable logistic regression analysis was used to explore the relationship between IVH (Grades I-IV), and each analyte in conjunction with covariates. Univariate analysis showed that maternal serum concentrations of IL-6 and CRP but not MMP-9 above the 90th percentile at the time of randomization were associated with preterm birth <32 weeks. Logistic regression analysis (see table) for each analyte indicated that high levels of IL-6 and CRP but not MMP-9 were also associated with an increased risk of IVH after adjusting for gestational age at randomization, and treatment group. When gestational age at delivery was included, elevated IL-6 remained significantly associated with IVH (OR 2.77, 95% CI 1.02-7.09). Elevated maternal serum CRP and IL-6 are risk factors for preterm birth <32 weeks and subsequent development of neonatal IVH. Elevated IL-6 appears to confer additional risk for IVH even after adjusting for gestational age at delivery.