Human chorionic gonadotropin (hCG) is a glycoprotein hormone produced first by the developing embryo after fertilization and subsequently by the syncytiotrophoblast, a part of the placenta. Its main function is to ensure the nutritional and hormonal factors and protection that the embryo needs for its development.
for its development.
And how does it do this? First of all, its secretion is the main factor for the maintenance of the corpus luteum, which is the remains of the ovarian follicle that remains after ovulation and will be responsible for the production of progesterone until the placenta can take care of it. In the absence of pregnancy, i.e. hCG, the corpus luteum degenerates, hormone levels drop and menstruation is triggered. It also stimulates the production of other hormones such as estrogens at the adrenal and placental levels and stimulates the fetal testes to secrete increasing amounts of testosterone to induce internal virilization of the embryo.
hCG is immunosuppressive, which is why we get colds more easily during pregnancy and may be involved in maternal lymphocyte function. This could be involved in the development of maternal immunotolerance and thus prevent maternal immune rejection of the embryo during early gestation.
Finally, hCG has a thyrotropic activity, so several physiological changes occur in the pregnant woman that causes adjustments in the thyroid axis. In addition, measurements of hCG, also known as the pregnancy hormone, have a clinical application, on the one hand, it will be useful for the diagnosis of pregnancy,
confirming its presence in both urine and blood.
In general, we can detect it in the blood from the eighth day after fertilization and in urine about 14 days after fertilization. On the other hand, it is also worth mentioning that free beta hCG levels are evaluated, together with other parameters in the triple screening test performed in the first trimester of gestation to determine the risk of chromosomopathy, since the secretion of this hormone may be increased in cases of Down syndrome, where up-regulation occurs as an effect of the extra chromosome 21.