Doubling of one indicator and lowering of the others in the first trimester of pregnancy may be a sign of miscarriage or ectopic pregnancy, and an obstetric ultrasound may be carried out to continue to monitor the changes in blood values. The main blood markers to monitor in early pregnancy are the human chorionic gonadotropin (HCG) level and the progesterone level. Under normal circumstances, HCG growth in early pregnancy tends to double. HCG is a pregnancy-specific hormone secreted by the trophoblast cells of the embryo, and a doubling of HCG in the early stages of pregnancy suggests that the embryonic cells are actively proliferating and that the embryo is growing well. Other low indicators may refer to progesterone, which is secreted by the mother’s ovaries before the 10th week of pregnancy, and synthesized and secreted by the placenta after the 10th week of pregnancy, and is an important hormone that supports the development of the embryo. If the progesterone level is low, it suggests the possibility of miscarriage or ectopic pregnancy. In this case, further obstetric ultrasound examination and subsequent dynamic observation of the doubling of blood HCG are needed to make a comprehensive judgment.