Abortion is the most common complication of pregnancy. Miscarriage occurs in approximately 50% of all possible pregnancies, and among women with clinically confirmed pregnancies, spontaneous abortion occurs in 15% to 20% of pregnancies, of which 1% to 5% develop RSA.
The etiology of RSA is very complex, it may be a single factor leading to miscarriage, or it may be a mixed multi-factor leading to miscarriage. The main causes of RSA are genetic factors, reproductive tract anatomical structural factors, endocrine factors, infectious factors, thrombotic disease factors, immune factors and male factors. Others include environmental factors, mental factors, drug factors, nutritional factors and RSA of unknown cause.
In the past 30 years, the diagnosis and treatment technology of RSA has developed by leaps and bounds. Studies have found that at least 40% of RSA patients have unknown etiology, and more than 80% of unexplained spontaneous abortions are related to immune factors. The vast majority of unexplained spontaneous abortions belong to alloimmune RSA. After partially attributing RSA to immune factors, either immune stimulation or immunosuppression are considered appropriate interventions. Pre-pregnancy genetic counseling, preimplantation genetic diagnosis (PGD), correction of reproductive tract anatomy, treatment of reproductive tract infection, regulation of endocrine dysfunction, treatment of immune abnormalities, and combination of endocrine therapy and immunotherapy after early pregnancy Precautionary measures have increased the success rate of RSA to a gratifying 70% to 90%.