The HCG value on the 28th day of pregnancy will generally be around 100 IU/L. The time of pregnancy is counted from the first day of the last menstrual period, but HCG will be produced in the body when the fertilized egg is laid, after which it will increase rapidly at the rate of doubling every two days, and will reach around 100 IU/L about two weeks after ovulation, and this time is about 28 days of pregnancy. With the prolongation of pregnancy, HCG will continue to increase rapidly, reaching a peak state in 8-10 weeks of pregnancy, and then decreasing rapidly, but there is a large normal range of HCG in the same pregnancy time, and there is a big difference in the examination data between individuals, so we cannot judge whether it is normal by the data of one examination. If you have a history of adverse pregnancy, you may consider the possibility of ectopic pregnancy.