A blood test for early pregnancy is also known as a blood HCG test, which is usually done after a history of menopause, usually by drawing blood from a vein at the elbow and sending it for testing, without fasting. The result of blood HCG can qualitatively determine whether pregnancy is present or not, the normal range is 0-5mIU/ml, and if it is higher than the normal range, it can qualitatively determine pregnancy, and the blood test can be repeated after 2-3 days to reflect the activity of the embryo. In general, the level of HCG doubles with the number of days of menopause after pregnancy, so a doubling of blood HCG confirms that the embryo is developing normally. However, whether the pregnancy is intrauterine or ectopic, whether the embryo develops with a germ and a fetal heart, and whether it corresponds to the number of days of menopause, all of these need to be examined by ultrasound.