RETN and gestational diabetes: Condensing the evidence on adipokines in placenta and umbilical cord, we can state that GDM is characterized by elevated placental expression of TNF-α, NGAL, resistin, and visfatin, and increased levels of leptin, TNF-α, NGAL, RBP4, visfatin, and decreased concentrations of adiponectin, AFABP, and fetuin A in umbilical cord.