Human chorionic gonadotrophin is a glycoprotein secreted by the
trophoblastic cells of the placenta. Human chorionic gonadotrophin (HCG) - - is
synthesized from syncytiotrophoblast cells.
The absolute value of serum human chorionic gonadotropin varies greatly
between different periods of pregnancy and among pregnant women. General
non-pregnant women: blood HCG(8-32)×104IU/L(urine human chorionic gonadotropin
level is the highest in the morning, close to the serum level). Human chorionic
gonadotropin as long as higher than the reference value given on the test sheet,
it can be indicated that pregnancy. Different hospital assay method is
different, so the reference value on the laboratory sheet is different, the
reference value of some hospitals is 0-5, so the human chorionic gonadotropin is
greater than 5, is pregnant. Some hospital reference value is 0-25, so the human
chorionic gonadotropin is greater than 25, is pregnant.
Human chorionic gonadotrophin enters the mother's blood after fertilization
and proliferates rapidly until the 8th week of pregnancy, then slowly decreases
in concentration until the 18th to 20th week, and then remains stable. In an
average intact human, chorionic gonadotropin levels rise to at least 2.5 MoM
before being associated with down syndrome. However, the average level of human
chorionic gonadotropin in the mother blood of DS patients was only 1.3MoM, which
could not clearly identify DS patients. The human chorionic gonadotropin-related
molecules used for DS examination had free b-hcg and high glucose
hCG(h-hcg).