Simultaneously, pro-inflammatory mediators as TNF-a and IL-1ß down-regulate ABCB1 mRNA and P-gp levels in human primary placental trophoblast cells [55, 56], which in circumstances as chorioamnionitis, will likely lead to a regulatory loop consisting of P-gp suppression and progressive accumulation of inflammatory factors in the intrauterine environment. Here, TNF is linked to chorioamnionitis.