Interleukin-6 -174 genotype, periodontal disease and adverse pregnancy outcomes: a pilot study

This study was undertaken to investigate whether maternal periodontal disease and variant genotypes of IL-6 gene are associated with adverse pregnancy outcomes. A total of 145 pregnant women were recruited from St Mary's Hospital, Manchester, UK. Bleeding on probing (BOP) and pocket depth indices were recorded on all teeth. Amplification refractory mutation system-polymerase chain reaction was used for -174 IL-6 genotyping. Birth weight was assessed using the individualized birth ratio (IBR) with intrauterine growth restriction (IUGR) defined as an IBR below the fifth percentile. The G/G genotype results in more BOP % sites in Caucasian (P < 0.001) and Afro-Caribbean pregnant women (P = 0.035). In addition, a marginal significant association between the -174 C/C genotype and IUGR was observed (P = 0.06). The -174* C allele was more frequent in women with IUGR than in normal women (63 vs 37%, P = 0.05). Moreover, the combination between the carriage of -174C allele and increased bleeding sites have increased the risk of IUGR (P = 0.006). Future studies, with a larger sample size, are required to better clarify the relationship between the IL-6 gene polymorphism, periodontal disease, and IUGR.