Biochemical pregnancies are early and early miscarriages, most of which are clinically asymptomatic and can have a few days of delayed menstruation and a slightly heavy and prolonged menstrual flow. There are very many reasons for this occurrence. An occasional occurrence is considered to be episodic, a sign of eugenics, and does not need to be treated. If it occurs twice or more in a row, the relevant treatment must be carried out. The main causes of biochemical pregnancy in clinical practice are the following: first, chromosomal problems, including chromosomal abnormalities in both spouses or in the embryo after pregnancy. Secondly, the mother has serious medical diseases, such as anemia, high fever, tumor diseases, etc. Third, the mother has endocrine disorders, such as thyroid abnormalities and polycystic ovary syndrome. Fourth, the mother has immune system diseases, or positive anti-sperm antibodies, positive anti-endometrial antibodies, etc. Fifth, the mother has a malformation of the reproductive tract, such as unicornuate uterus, longitudinal uterus, etc. Sixth, the mother has tumor diseases of the reproductive system, such as uterine fibroids, adenomyosis, endometrial polyps, submucosal fibroids, etc.