HCG, also known as human chorionic gonadotrophin, is a glycoprotein
secreted by placental trophoblast cells. After fertilization, HCG can enter the
mother's blood and rapidly increase in value until the 8th to 10th week of
gestation, and then slowly decrease in concentration until it reaches a stable
level at the 18th to 20th week.
How is HCG produced? As the fertilized egg lays, it stretches out its
dendritic tentacles, which are called hairs, and grabs onto the wall of the
uterus, where it forms an early placenta. Before the placenta matures, the hairs
become thick and attach to a thin membrane. These chorionic membranes are
gradually filled with blood vessels, which form the primary link between the
mother and the embryo, metabolizing waste. The growth of this villi is what we
call a doubling, with HCG levels roughly doubling every 2.2±0.5 days during the
first 3 months of pregnancy. The absolute value of serum HCG varies greatly
between different periods of pregnancy and between pregnant women, and there is
no comparability between them, only their own comparison can be made. So you
don't have to compare yourself to others, as long as your HCG increases
normally. However, if the reexamination of HCG is still not doubled or doubling
is not good, biochemical pregnancy or ectopic pregnancy should be considered.
Ectopic pregnancy is usually accompanied by obvious symptoms, such as low
progesterone, abdominal pain, bleeding, etc. You should see a doctor.
Another very important function of HCG is to reduce the rejection reaction
of pregnant women. You have a parasite on you, and in general, your immune
system is going to attack, but HCG is confusing the mother, telling her it's
safe, it's your own, so your immune system doesn't fire. The synergistic effect
of HCG and progesterone, on the one hand, enables the embryo to obtain
nutrients, on the other hand, guarantees the safety of the embryo, so neither is
indispensable. The doubling of HCG is not good. Because of the lack of nutrients
in the embryo, it may be stunted or even stop breeding. Without enough
progesterone, the embryo may become unstable, causing bleeding and even
miscarriage. However, the low value of HCG and progesterone does not mean that
the abortion will be inevitable, but the probability will be high. Once there is
bleeding, you should go for a check. If you have a bad pregnancy history, you
can monitor it just in case.