The interleukin-6 −174 single nucleotide polymorphism: Cervical protein production and the risk of preterm delivery

Objective The purpose of this study was to determine the associations between preterm delivery (PTD), cervical fluid interleukin-6 (IL-6) concentration, and the single nucleotide polymorphism at position −174 in the IL-6 gene. Study design Cervical fluid samples were obtained from women 23 to 32 weeksʹ gestation with symptoms of preterm labor. Concentrations of IL-6 were determined by enzyme-linked immunosorbent assay (ELISA). IL-6 genotyping was performed using a polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) technique. Results One hundred thirty-seven women were enrolled, and complete information was available for 126. Cervical fluid IL-6 concentrations were not elevated in women destined to have a spontaneous PTD (P = .86). IL-6 −174 genotype was not associated with PTD (P = .62) or cervical fluid IL-6 concentration (P = .36). Neonatal IL-6-174 genotype was not associated with PTD or IL-6 concentration. Conclusion Cervical fluid concentrations of IL-6 were not elevated in symptomatic women destined to have a spontaneous PTD. The presence of maternal IL-6 −174C was not associated with cervical fluid concentration of IL-6 or risk of PTD.