HCG doubling is recommended to be checked at least 1-2 times and 2 days apart. HCG usually doubles after the first week of pregnancy, and if the HCG level doubles normally 1-2 times, there is usually no need to check again. As HCG values continue to rise in early pregnancy, but HCG can not be strictly doubled, so it is not recommended to repeat the screening. HCG doubling conditions include the following: 1, doubling normal: HCG and progesterone synergistic effect to protect the fetus, so when pregnant women with normal HCG doubling, progesterone is also within the normal range, it can indicate that the current healthy development of the fetus; 2, doubling is too low: if the HCG doubling Low: If HCG doubling is low, it usually suggests that the embryo development is retarded, at this time, pregnant women can be treated with fertility preservation, if HCG continues to rise, it indicates that the effect of fertility preservation is good; if pregnant women’s blood HCG is obviously low (<2500IU/L) or continuous monitoring of the downward trend, it indicates that there is a possibility of miscarriage or stillbirth. If pregnant women have abdominal pain, bleeding, anal pain symptoms, do not rule out the possibility of ectopic pregnancy, need to go to the hospital in time for ultrasound examination; 3, doubling too high: some pregnant women for the gravidarium, trophoblast cells highly proliferative can produce a large number of HCG, which in turn cause HCG doubling too fast, it is recommended that pregnant women through further ultrasound examination to determine if the diagnosis of gravidarium as soon as possible need to carry out purging surgery, and regular checkups, to avoid the possibility of chorioamniosis. If the diagnosis of hyperemesis gravidarum is confirmed, the pregnant woman should undergo surgery as soon as possible and have regular checkups to avoid chorionic villus.