Human chorionic gonadotropin 0.1nmol/L is a non-pregnant state, indicating that there is no pregnancy, and a general blood value of 5nmol/L or more is pregnancy. Five days after ovulation, the embryo is implanted and the trophoblast cells of the ectoderm of the embryo begin to secrete human chorionic gonadotropin, which can be detected in the blood. The blood value is low at first, but by two weeks after ovulation, it rises to about 200 nmol/L and increases every other day, reaching 1.7-2.0 times. Blood human chorionic gonadotropin is a direct reflection of the goodness of the embryo. If the doubling is not normal and the blood value is too low, there may be a biochemical or ectopic pregnancy, or there may be a fetal arrest. That is why it is important to recheck HCG after pregnancy and to see an ultrasound two weeks after pregnancy to see if it is an intrauterine pregnancy.