Romero et al. [36] showed evidence for the contribution of IL-1β to preterm birth: (1) IL-1β is produced by human decidua in response to bacterial products; (2) IL-1β can stimulate prostaglandin production of human amnion and decidua; (3) IL-1β concentration and bioactivity were increased in the amniotic fluid of women with preterm labor and infection; and (4) IL-1β could stimulate myometrial contractions [36]. Here, IL1B is linked to infection.