RARRES2 and gestational diabetes: These proteins included protein-arginine deiminase type II (PADI2), a peptidylarginine deiminase that is responsible for protein citrullination and implicated in parturition and sensing infections40,41; transferrin receptor (TfR), which is implicated in iron transport; angiopoietin-like 4 (ANGPTL4), which regulates glucose homeostasis and lipid metabolism42; and RARRES2, an adipokine that is increased in metabolic syndrome and gestational diabetes.43,44