Human Chorionic Gonadotropin (hCG) is a hormone that plays a vital role in human reproduction. It is produced by the placental cells following implantation of the fertilized egg in the uterus. Structurally, hCG is a glycoprotein composed of two subunits, alpha and beta, where the alpha subunit is identical to that of other hormones like LH (Luteinizing Hormone), FSH (Follicle Stimulating Hormone), and TSH (Thyroid Stimulating Hormone), while the beta subunit is unique, distinguishing it from these other hormones.
The primary function of hCG is to support the corpus luteum, which is a temporary endocrine structure involved in early pregnancy. The corpus luteum secretes progesterone, a hormone crucial for maintaining the uterine lining and creating a suitable environment for the developing embryo and fetus. By stimulating the corpus luteum to produce progesterone, hCG ensures that the uterine lining remains intact and provides the necessary nutrients and environment for the embryo to grow.
hCG levels rise rapidly during the early stages of pregnancy, making it an essential marker for pregnancy tests. These levels peak around 8 to 11 weeks of pregnancy and then gradually decrease and level off for the remainder of the pregnancy.
In addition to its role in maintaining pregnancy, hCG also influences the development of fetal organs and plays a part in maternal immunotolerance, helping the mother's body to not reject the fetus as foreign tissue.
hCG's involvement in reproductive processes makes it a focus of interest in fertility treatments. It is often used in assisted reproductive technologies (ART) to trigger ovulation and prepare the endometrium for implantation in procedures such as in vitro fertilization (IVF).
Understanding the biochemical properties and physiological roles of hCG is essential for advancing reproductive medicine and enhancing fertility treatments, providing insight into its critical function in the early stages of pregnancy.