When a biochemical pregnancy occurs, there is no gestational sac. Biochemical pregnancy refers to the combination of sperm and egg to form a fertilized egg, but the fertilized egg does not attach to the bed, that is, there is a miscarriage, also known as insidious miscarriage, subclinical miscarriage. When biochemical pregnancy occurs, there is no gestational sac tissue outflow, and the symptoms are similar to ordinary menstruation, mainly manifested as a few days delayed menstruation, menstrual flow increased compared with the previous, and some patients have lower abdominal pain similar to dysmenorrhea. The menstrual blood may be mixed with shed meconium tissue. The etiology of the occurrence of biochemical pregnancies is not fully understood and may be related to issues such as the woman’s age, the state of the uterine lining, the endocrine profile and the quality of the man’s sperm. However, it is also a manifestation of eugenics. An occasional biochemical pregnancy will not affect the next normal pregnancy. After a biochemical pregnancy, women should pay attention to adjusting their state of mind, taking proper rest and supplementing nutrients. If biochemical pregnancy occurs frequently, she should actively seek medical examination and treatment.