Frequent HCG tests are not necessary if the pregnancy is confirmed to be intrauterine and the embryo is developing well, but if the patient has abdominal pain, bleeding or other signs of preterm miscarriage, or if the pregnancy is unique and it is difficult to determine whether the pregnancy is intrauterine or extrauterine. In this case, frequent HCG tests are needed to observe the activity of the gestational sac and to guide the clinical management of the pregnancy, or to help determine whether the pregnancy is intrauterine or extrauterine.