hCG refers to human chorionic gonadotropin. In normal pregnancy, trophoblast cells are formed and begin to secrete hCG a few days after the fertilized egg is laid, but luteal insufficiency in pregnant women may cause the embryo sac and appendages to develop poorly and lead to insufficient secretion of hCG by trophoblast cells, resulting in a decrease in hCG. According to research, small doses of hCG can promote the function of the corpus luteum in early pregnancy and increase the stability of embryo development. The more hCG injections are given in the early stages of pregnancy, the better. In case of ectopic pregnancy, hCG injection can promote the activity of ectopic pregnancy, so it is more important to observe closely to avoid such situation. In order to avoid such situation, you can find out the embryonic development by taking blood test for beta-hCG every 2-3 days in early pregnancy. In normal early intrauterine pregnancy, the beta-hCG value rises faster every 24 hours; every two to three days the beta-hCG value can double while in the presence of ectopic pregnancy, the beta-hCG value generally rises slowly. Ultrasound is the gold standard for differentiating intrauterine pregnancy from ectopic pregnancy. Special attention should be paid to those who have a history of miscarriage or bad pregnancy, who have had hCG injections in early pregnancy or who have been preserved by other means, should have ultrasound to screen for the presence of ectopic pregnancy at 5-6 weeks of menopause for early detection and treatment to reduce the risk.