An lnterleukin-6 Gene Promoter Polymorphism and Unexplained Late Intrauterine Fetal Death: A Multicenter Study

Abstract

Interleukin-6 (IL-6)-mediated inflammatory processes have been proposed to be involved in the pathogenesis of pregnancy-associated complications such as late unexplained intrauterine fetal death (IUFD). Therefore we determined whether a common guanine/cytosine polymorphism at position -174 of the promoter of the IL-6 gene (IL6) known to affect in vivo protein activity can serve as candidate gene for this condition. In a multicenter case-control study, we evaluated the IL6 promoter polymorphism by pyrosequencing in 92 women with IUFD. Ninety-four healthy women with at least one uncomplicated full-term pregnancy and no history of IUFD served as the control group. No significant association was found between the presence of at least one mutant allele of the IL6 promoter polymorphism (P = .2; odds ratio = 1.5 [95% confidence interval, 0.8-2.7]) and the incidence of IUFD. In women with IUFD, the presence of at least one mutant allele of the IL6 promoter polymorphism did not influence timing of fetal death (33.9 [5.1] gestational weeks vs 34.1 [4.9] gestational weeks, P = .8) or birth weight (2055 [1119] g vs 1963 [992] g, P = .7). To our knowledge, we are the first to report on a common polymorphism of the IL6 promoter gene in women with late IUFD. The investigated IL6 promoter polymorphism can not be seen as candidate gene for IUFD in Caucasian women.