Two biochemical pregnancies require more items to be examined, including chromosome examination, immunity examination, uterine adnexa ultrasonography, systemic examination, thyroid function examination and male sperm examination. 1. Chromosome examination: both husband and wife need to undergo chromosome examination. If either of the husband or wife has chromosome abnormality, there will be chromosome abnormality in the embryo, and then biochemical pregnancy will occur, which is the main cause of biochemical pregnancy. 2. Immunity examination: it can determine whether the woman suffers from lupus erythematosus and other immune system diseases, such diseases can affect the fertilized egg implantation, which in turn leads to biochemical pregnancy. 3. Ultrasound examination of uterine adnexa: it can determine whether a woman has uterine-related organic lesions, such as uterine fibroids, endometrial polyps, or uterine malformations such as mediastinal uterus, and such diseases can also affect the fertilized egg implantation, leading to the occurrence of biochemical pregnancy. 4. Systemic examination: such as infectious disease examination, liver function test, electrocardiogram, etc., to check whether there are other diseases. Diseases can easily affect the implantation of the fertilized egg, thus leading to biochemical pregnancy. 5. Thyroid function test: check whether there is hypothyroidism or hyperthyroidism, etc. Abnormal thyroid function will affect the endocrine level, leading to biochemical pregnancy, miscarriage, preterm labor, etc. 6. Male sperm examination: the quality of male sperm can be observed. Abnormalities in sperm vitality and sperm morphology will affect the implantation of fertilized eggs and lead to biochemical pregnancy in women. After a series of tests mentioned above, to know whether there is any abnormality, and then give treatment when abnormalities are found, it helps to avoid the possibility of biochemical pregnancy.