What is HCG secreted by?

Human chorionic gonadotropin (HCG) is primarily secreted by the placenta during pregnancy. It is produced by the cells that form the placenta shortly after implantation of the fertilized egg. HCG plays a crucial role in maintaining the corpus luteum, which produces progesterone to support the pregnancy in its early stages. Additionally, HCG is involved in the development of fetal organs.