Human chorionic gonadotrophin (HCG) is a glycoprotein secreted by placental trophoblastic cells during pregnancy, consisting of alpha and beta subunits.
The alpha subunit is also a component of other hormones such as FSH, LH and TSH, while the beta subunit only exists in HCG, so it is usually β-HCG that is widely used and detected clinically. The HCG involved in this paper is also β-HCG.
Here are the functions of HCG
1, Normal pregnancy
The main role of HCG is to maintain the secretory function of the luteal corpus of the ovary during the first few weeks of gestation to support the needs of early embryonic development.
Clinically, the threatened abortion of early pregnancy can be evaluated by monitoring the β-HCG and serum progesterone levels of 4 to 7 weeks of early pregnancy, so as to prevent the occurrence of threatened abortion, which is of great significance for clinical diagnosis
2, Ectopic pregnancy
Implantation of a fertilized egg outside the uterine body cavity is called ectopic pregnancy. Ectopic pregnancy Due to placental development restriction, HCG production is low, so the maternal serum HCG level of ectopic pregnancy is lower than the normal pregnancy level.
Serum β-HCG combined with progesterone has obvious effect on the early diagnosis of ectopic pregnancy, with high accuracy, sensitivity and specificity, and can be used as an auxiliary means for the early diagnosis of ectopic pregnancy
3, Hydatidiform mole and chorionic carcinoma
Due to the high proliferation of trophoblast cells in hydatidiform mole, a large amount of HCG is produced, and the concentration of HCG is usually significantly higher than the normal gestational cycle value corresponding to normal pregnancy, and continues to decline. If the mole degenerates and does not continue to grow, HCG levels may be low. Of course, abnormally elevated HCG is an auxiliary diagnostic indicator for hydatidiform mole, and diagnosis should be combined with B-ultrasound and other examinations, but HCG is of great significance in regular follow-up after surgery.
HCG measurement is an important indicator for the diagnosis of choriocarcinoma, which can come from hydatidiform mole, abortion (including ectopic pregnancy, induced abortion) or full-term pregnancy. β-HCG plays an important role in the diagnosis, differential diagnosis, outcome, prognosis and clinical staging of hydatidiform mole, invasive hydatidiform mole and choriocarcinoma, but it still needs to be combined with B-ultrasound, CT and pathological diagnosis
In this articles, we learn the 3 functions of HCG. For more functions of HCG, please refer to our article “The functions of HCG (Part. 2)”.