Medically, we call the termination of pregnancy less than 28 weeks and the fetus weighing less than 1000g as miscarriage; the gestational week less than 12 weeks is called early miscarriage. About 2/3 of early miscarriages are occult miscarriages, which refer to miscarriages that occur before menstruation, i.e. biochemical pregnancies; therefore, miscarriages less than one month are biochemical pregnancies. In a true miscarriage, there are usually symptoms such as vaginal bleeding and abdominal pain after menopause, but in a biochemical pregnancy, there are usually no such symptoms, which is now medically called subclinical miscarriage. In life, for miscarriages that occur in less than one month, patients often have no obvious history of menopause, and most of them do not realize that they are pregnant and miscarried, thinking that it is just a delayed menstrual period, which does not attract much attention; they need to go to the hospital for examination and diagnosis by blood and urine HCG (human chorionic gonadotropin) measurement and vaginal ultrasound, if the blood HCG is elevated (more than 25miu/ml), or the urine pregnancy test is positive The diagnosis of biochemical pregnancy can be made if the blood HCG is elevated (>25miu/ml) or if the urine pregnancy test is positive, but the gestational sac is not visible on vaginal ultrasound, combined with a menopause of less than 5 weeks. In fact, spontaneous abortion occurs in about 31% of patients in early pregnancy due to various factors, of which early abortion accounts for 80%; the most common cause is chromosomal abnormality of the embryo or fetus; in other words, for women of normal childbearing age, the emergence of subclinical abortion less than one month, do not panic, the development process of the fertilized egg is like the history of human growth and evolution, it is a race to the bottom. The development of the fertilized egg is like the evolutionary history of human growth, a process of survival of the fittest. The occurrence of a biochemical pregnancy does not usually affect the next pregnancy.