The earliest clinical determination of pregnancy can be made by checking the patient’s blood for HCG levels. It usually takes 6-7 days at the earliest to produce human chorionic gonadotropin shortly after fertilization of the egg, so a pregnancy test can be used about 6-7 days after fertilization to test for the presence of a positive pregnancy. The principle of the pregnancy test is to determine the amount of human chorionic gonadotropin in the urine. Human chorionic gonadotropin really starts to be produced in large quantities after the egg is laid, because this is when the syncytial trophoblast cells start to secrete and produce human chorionic gonadotropin in large quantities, and it takes at least 11 days for the egg to be laid. Therefore, it is recommended to wait for 11 days after intercourse for accurate measurement results. For urine pregnancy tests, a more definitive measurement is usually available in 20 days. The blood test, on the other hand, can only be measured after at least 30 days, otherwise the concentration of progesterone in the blood is not enough and the result is not accurate. Usually the above tests cannot determine the intrauterine pregnancy, so an ultrasound test is also needed at the same time. The gestational sac is usually visible on ultrasound at 35 days of menopause, and the germinal bud and primitive heart tube pulsation are visible at 42 days. Ultrasound is usually done 3-5 times during pregnancy, once in early pregnancy to determine pregnancy and diagnose common diseases in early pregnancy such as ectopic pregnancy and hyperemesis gravidarum. In the middle of pregnancy, that is, 22-26 weeks of pregnancy, 4D ultrasound screening is done to clarify whether the fetus has any major malformations and major organ malformations. For women of childbearing age, in good health and with a history of sexual intercourse, if symptoms such as menopause, early pregnancy reaction and frequent urination occur, pregnancy should be highly suspected and timely relevant examinations are recommended for a clear diagnosis.