EG-VEGF was characterized as an angiogenic factor with selective activities mainly on endothelial cells, which are derived from endocrine glands. Also, this protein was named prokineticin 1 and was identified as the mammalian homologs of snake MIT1 protein. Two prokineticins, PROK1 and PROK2 (Bv8) were identified, and they have 44 % of identity at the amino acid level. EG-VEGF and PROK2 are structurally related to a larger class of peptides, which are defined by a five disulphide-bridges motif called a colipase fold. Additionally, EG-VEGF and PROK2 share the same G protein-coupled receptors, which are designated PROKR1 and PROKR2. In the heart and placenta, PROKR1 is preferentially involved in proliferation and angiogenic processes and PROKR2 is mainly implicated in endothelial permeability. EG-VEGF mediates effects on the fetomaternal angiogenesis during the first trimester of pregnancy. Abnormal placenta angiogenesis is associated with pregnancy-related pathologies such as ectopic pregnancy, recurrent pregnancy loss, gestational trophoblastic diseases, preeclampsia, and fetal growth restriction.