Interleukin 6-174 G/C promoter polymorphism and pregnancy complications: results of a prospective cohort study in 1626 pregnant women.

PROBLEM: To investigate the frequency of the interleukin-6 (IL-6) -174 G/C single nucleotide polymorphism (SNP) in women with intrauterine fetal death (IUFD), pre-eclampsia (PE), preterm delivery (PD), and small for gestational age (SGA) infants. METHOD OF STUDY: In a prospective cohort study, DNA from 1626 consecutive pregnant women was analyzed for IL-6 -174 G/C. Women who developed at least one of the predefined pregnancy complications were used as cases and compared with women without pregnancy complications. RESULTS: Of 1626 women, 259 (15.9%) developed at least one pregnancy complication. IL-6 -174 G/C allele frequencies and genotype distributions were not significantly different between cases and controls. Similarly, no statistically significant difference in IL-6 -174 G/C genotype distribution in women with IUFD, PE, PD 34 weeks and SGA infants <10th percentile was observed. CONCLUSION: IL-6 -174 G/C is not a genetic marker for identifying women at increased risk of common pregnancy complications.