The average value of HCG on the 42nd day of pregnancy is around 16870. However, if there is a delay in every menstruation, including a late onset of labor, late ovulation, or a prolonged menstrual cycle, this will affect the onset of labor and will affect the value of HCG. If the doubling is very obvious, it indicates that the fetus is developing very well and the chance of intrauterine pregnancy is very high; if the doubling is not particularly obvious, there is a chance of ectopic pregnancy and preterm miscarriage. At this time, it is recommended to combine the progesterone test to determine whether it is normal or not, and depending on the situation, preventive fertility treatment can be carried out to avoid the chance of preterm abortion due to the drop in HCG. If the progesterone level is very low below 10, it is not advisable to carry out birth control at this time, because the chance of ectopic pregnancy is very high.