TNF and gestational diabetes: Since it is well-understood that IL-38 is an anti-inflammatory cytokine, increased IL-38 in GDM probably contributes to the suppression of the highly inflamed placenta and umbilical cord during the GDM condition, which is in line with significantly upregulated proinflammatory cytokines (IL-6 and TNF) in the GDM placenta (45), and the higher levels of systemic and local proinflammatory cytokines in the diabetic condition (12).