The level of blood HCG is not indicative for the confirmation of ectopic pregnancy and the exclusion of ectopic pregnancy depends on gynecological ultrasound. Internal gynecological examination is very important. In early pregnancy during the 4-8 weeks of menopause, blood HCG shows a rise of at least 66% every 3 days in normal pregnant women and this pattern of rapid increase in blood HCG is known as HCG doubling. In case of ectopic pregnancy, poor doubling of blood HCG may occur, such as a slow rise in blood HCG without typical doubling, or a persistent low level of blood HCG, or a decrease in blood HCG level when the ectopic gestational sac is metastasizing naturally, but when the gestational sac is in the horn of the uterus or the cervical area where the blood supply is better, although it is also an ectopic pregnancy, it can occur due to the rich blood supply in the area of implantation The presence of a good doubling of blood HCG needs to be alerted. In addition, intrauterine pregnancy with preeclampsia can also present with the above-mentioned poor doubling of blood HCG, which can be treated with fertility preservation, but the differentiation from ectopic pregnancy still depends on gynecologic ultrasound, and the doubling of blood HCG can only be used as an auxiliary reference.