Similarly, Arntzen et al. (1998) [24] quantified the levels of TNF-α, IL-1, IL-6, and IL-8 in the amniotic fluid of women with preterm and full-term labor and found an association between increases in TNF-α, IL-1, and IL-6 levels and preterm delivery, suggesting that IL-1 plays a dominant role in the presence of chorioamnionitis, whereas IL-6 seems to be more important during preterm idiopathic delivery. This evidence concerns the gene IL1B and chorioamnionitis.