Galectin-13 (Gal-13) is a glycan-binding protein that regulates innate and adaptive immune responses. It is predominantly expressed by the syncytiotrophoblast and released from the placenta into the maternal circulation. It has the ability to induce apoptosis of activated T cells in vitro, and divert and kill T cells as well as macrophages in the maternal decidua. Gal-13 with its anti-inflammatory functions plays a role in regulation of maternal immune system, a lack of gal-13 contribute to an imbalance in inflammation processes in the placenta during pregnancy and therefore influences development of gestational diabetes mellitus (GDM). Gal-13 levels are low in the first trimester of pregnancy that confers a higher risk for developing pre-eclampsia later in pregnancy.