Biochemical abortion refers to the pathology caused by the fertilized egg that does not develop in the uterine cavity, also known as biochemical pregnancy, the main reasons include the fertilized egg factors, maternal factors, paternal factors, environmental factors, and so on. 1. Fertilized egg factor: if the fertilized egg has chromosomal abnormalities caused by developmental disorders, may cause the fertilized egg can not be in the uterine cavity of the normal implantation, may cause biochemical abortion. 2. Maternal factors: If the mother has congenital malformation of the uterus, uterine fibroids, endometriosis, endocrine disorders, long-term smoking and alcohol abuse, etc., it may lead to impediments to the implantation of the fertilized egg, which may lead to biochemical abortion. 3. Father’s factor: the father’s sperm abnormality rate is relatively high, may lead to abnormal development of the fertilized egg caused by biochemical abortion. 4. Environmental factors: Biochemical abortion can easily occur if you have been exposed to a lot of radioactive substances, toxic and harmful chemical substances for a long time.