HCG, or human chorionic gonadotropin, can increase the level of HCG in the peripheral blood after the fertilized egg has been deposited. Generally speaking, pregnancy can be suspected if the HCG level rises above 10 mIU/ml, but it should be judged in combination with other tests. In early pregnancy, it is normal for HCG to double every other day. If the HCG doubles abnormally, we should be alert to whether there is a poorly developed gestational sac or ectopic pregnancy, so further tests should be done to rule out abnormalities. Generally, about 10 days after intercourse, a blood test for HCG can assist in determining whether or not you are pregnant. In addition, increased levels of HCG in the urine can only be diagnosed after half a month of intercourse. The diagnosis of pregnancy should not rely solely on the value of HCG, but should also be combined with the results of ultrasound and other tests to determine whether the pregnancy is normal.