Source of angiopoietin-2 in the sera of women during pregnancy

► Ang-2, but not Ang-1, is elevated in maternal serum compared to non-pregnant serum. ► The key source of the elevated Ang-2 during pregnancy is decidual endothelial cells. ► Ang-2 release by DECs relies on intracellular stores and newly synthesized protein. ► The pregnancy-induced rise in Ang-2 in maternal sera is attenuated in IUGR.