CGA also known as HCGα plays a crucial role in early pregnancy as it is produced by the placenta during the first trimester. This hormone exists as a heterodimer, consisting of a common α chain and a unique β chain, with the latter providing biological specificity to other hormones such as thyrotropin, lutropin, and follitropin. The α subunit is encoded by a gene located on human chromosome 6, while the β subunit is found on chromosome 19. CGA stimulates the ovaries to produce and maintain essential steroid hormones, including estrogen and progesterone, which are vital for sustaining pregnancy. Additionally, CGA is classified within the cystine knot growth-factor superfamily, characterized by a unique arrangement of six cysteine residues, which is significant for structural integrity and biological function.