Angiopoietin 1 is a type of angiopoietin and is encoded by the gene ANGPT1. Angiopoietins are proteins with important roles in vascular development and angiogenesis. All angiopoietins bind with similar affinity to an endothelial cell-specific tyrosine-protein kinase receptor. The protein encoded by this gene is a secreted glycoprotein that activates the receptor by inducing its tyrosine phosphorylation. It plays a critical role in mediating reciprocal interactions between the endothelium and surrounding matrix and mesenchyme. The protein also contributes to blood vessel maturation and stability, and may be involved in early development of the heart. During pregnancy, angiopoietins act complementary to the VEGF system and contribute to endothelial cell survival and the remodeling of vessels. Few studies have examined the role of angiopoietins in human pregnancy complications like preeclampsia and intrauterine growth restriction (IUGR).