Recurrent spontaneous abortion refers to three or more consecutive spontaneous abortions before 28 weeks, the incidence of which is about 0.5% to 3% of pregnant women of childbearing age. Human fertility is not considered a highly efficient biological process, with approximately 30% to 50% of spontaneous abortions in the first trimester resulting in the end of conception, with most abortions occurring at the time of embryo implantation. 15-20% of clinical pregnancies end due to spontaneous abortion. Recurrent miscarriage is a distressing clinical problem for clinicians and patients, but should be recognized as a natural process of elimination at the time of miscarriage. The identified causes of recurrent spontaneous abortion include: 1, embryonic chromosomal abnormalities: accounting for about 50% of the causes of miscarriage, 1 to 2% due to chromosomal abnormalities in the parents themselves, the rest are due to external factors and the embryo formation process is affected. 2.Uterus anatomical abnormalities: Diagnosis and treatment can be confirmed through ultrasonography, imaging, hysteroscopy, etc. 3.Endocrine abnormality:through luteal phase sex hormone examination, or post-pregnancy sex hormone examination to supplement the luteal function. 4.Reproductive tract infection:Pre-birth examination after pregnancy to exclude infection in pregnancy. 5, autoimmune diseases:such as thyroid function check, systemic lupus erythematosus, etc. 6, 50% of the causes are unknown, 80% of which are related to immune factors: anti-nuclear antibody, closed antibody examination, feasible aspirin, active immunity and other treatments.