What are the causes of recurrent spontaneous abortion? Recurrent miscarriage generally refers to 2 or more consecutive or non-consecutive spontaneous miscarriages, each often occurring in the same month of pregnancy. According to statistics, the incidence of recurrent miscarriage among married women is about 1-5%. The causes of recurrent miscarriage include genetic defects of the couple and the embryo, among which, chromosomal abnormalities of the couple are most common with balanced translocation, aging of the egg, chromosomal abnormalities of the sperm, adverse environment such as toxic chemicals, radiation and high temperature can cause chromosomal abnormalities of the embryo; uterine abnormalities: such as uterine malformation, submucosal myoma, cervical insufficiency or uterine adhesion syndrome, etc.; endocrine disorders: mainly Immune factors include autoimmune and alloimmune abnormalities; infection with Toxoplasma gondii, syphilis spirochetes, herpes simplex virus and cytomegalovirus are also causes of miscarriage; systemic diseases such as severe cardiovascular disease, renal disease, blood disorders can lead to miscarriage in pregnant women, systemic lupus erythematosus, scleroderma The incidence of recurrent miscarriage is significantly higher in patients with autoimmune diseases such as SLE and scleroderma; adverse factors in the environment, such as excessive exposure to harmful chemicals, decoration pollution, excessive exposure to radiation, severe noise and vibration, excessive physical labor, and bad habits such as alcoholism, smoking and drug addiction can also lead to spontaneous miscarriage. How to treat patients with recurrent miscarriage? First of all, 2-3 months before the next pregnancy, the patient should go to a regular hospital for a series of examinations, the main purpose of which is to find the cause of recurrent miscarriage and then treat the cause. The treatment of anatomical abnormalities of the reproductive tract includes plastic surgery for uterine deformities, separation of uterine adhesions, excision of uterine fibroids and intrauterine foreign bodies, etc. Cervical cerclage is a more effective method with an efficiency of 75~100 %. There is no effective treatment for miscarriage caused by chromosomal abnormality carriers, and its measures are mainly genetic counseling and estimation of the probability of recurrence of fetal chromosomal abnormalities. Carriers of autosomal balanced translocations and Robertsonian non-homozygous translocations can be pregnant, but prenatal diagnosis should be done, and preimplantation diagnosis for IVF is also possible to ensure the birth of a normal karyotype baby. For Robertson homozygous translocation carriers, it is not possible to have a child with normal karyotype and they should be advised to use contraception or to use donor normal gametes for in vitro fertilization-embryo transfer. Couples with normal chromosomes and abnormal chromosomes in the aborted product should avoid the influence of adverse environmental factors to prevent aging of eggs or sperm. After screening for etiology and excluding genetic, anatomical, infectious, and endocrine factors, most unexplained recurrent miscarriages are due to immune factors. After immunological examination, those with closed factor deficiency can be treated with active immunotherapy, in which the lymphocytes of the husband or a third party are injected as immunogens to induce the patient to produce individual-specific factors or closed factors that inhibit T-cell recognition of fetal antigens through allogeneic sensitization reactions. Currently, active immunotherapy with lymphocytes for recurrent miscarriage is routinely carried out in our hospital, and this treatment has been applied with excellent results, enabling many patients with recurrent miscarriage to have healthy babies.