There is no specific clinical HCG value to indicate the need for fetal preservation, and it varies from pregnancy to pregnancy, and it is usually not possible to determine the need for fetal preservation by HCG value alone. If the value is lower than about 60% of the normal value, you need to combine your symptoms and ultrasound examination to make a comprehensive judgment on whether it is necessary to keep the pregnancy. an HCG value greater than 20-50 U/L indicates pregnancy, and if the pregnant woman shows a significant decrease in HCG, or if the HCG value does not increase exponentially as the pregnancy cycle increases, it indicates the possibility of preterm miscarriage. After ruling out ectopic pregnancy, it is also necessary to combine with ultrasound and other examinations to observe the status of the fetal bud or fetus, the presence of fetal heartbeat, etc., and the doctor will confirm whether it is necessary to keep the fetus according to the examination results. If the ultrasound examination reveals abnormal gestational sac, the heartbeat never appears or gradually disappears, and the HCG value suddenly drops or does not increase significantly, the progesterone drops, or even vaginal bleeding, it is less likely to be successful and there is usually no need to keep the fetus. In some cases, if the HCG value continues to drop, even if the ultrasound indicates that the fetal heart is normal, the pregnancy may need to be cleared and birth control is not recommended. In addition to the drop of HCG, if a pregnant woman has symptoms such as vaginal bleeding, pain in the lower abdomen, discomfort in the lower back and loss of pregnancy response, she should also go to the hospital for relevant examination in time to determine whether it is a preterm abortion.