Miscarriage is defined as the termination of a pregnancy at less than 28 weeks and a fetus weighing less than 1000g. The incidence of spontaneous abortion in human pregnancies is about 50-60%. The risk of recurrence of spontaneous abortion increases with the number of miscarriages. The common factors of miscarriage are as follows: 1. Age: the rate of spontaneous abortion begins to rise for women older than 30 years old, up to 74.5% after 45 years old, and the risk of miscarriage gradually increases after 35-40 years old for men. 2, chromosomal abnormalities: chromosomal abnormalities include chromosomal abnormalities of both spouses and embryonic chromosomal abnormalities, the rate of embryonic chromosomal abnormalities is 46-54%, the earlier the miscarriage occurs, the higher the rate of embryonic chromosomal abnormalities. The rate of chromosomal abnormalities in one or both spouses is 4-7%, and the common ones are balanced ectopic, and the aborted products are often empty sacs or structurally abnormal embryos. The first affiliated hospital of Anhui University of Traditional Chinese Medicine, male department of Dai Ning 3, uterine malformation: longitudinal uterus, bicornuate uterus, unicornuate uterus, uterine dysplasia, etc. 4, uterine adhesion: a variety of physical and chemical factors damage the endometrium and myometrium leading to mutual adhesion of the uterine wall, severe adhesion can cause infertility, mild or moderate adhesion is closely related to miscarriage. 5, cervical insufficiency: pathological cervical dilatation is an important cause of late recurrent miscarriage and preterm delivery. 6, uterine fibroids: fibroids can deform the uterine cavity, stimulate uterine contraction, affect the blood supply to the endometrium, etc., and affect the development of the implanted egg. 7, infection: Mycoplasma, Chlamydia, toxoplasma, gonococcus, herpes virus, rubella virus, cytomegalovirus and other infections can cause early miscarriage. 8, endocrine factors: luteal insufficiency, polycystic ovary syndrome, hyperprolactinemia, thyroid disease, diabetes mellitus, etc. account for about 12-15% of recurrent miscarriages. 9, pre-thrombotic state: pre-thrombotic hypercoagulable state can lead to micro thrombus formation in the placental part of the uterus, resulting in embryonic ischemia, hypoxia, resulting in embryonic dysplasia or miscarriage. 10, immune disorders: 50-60% of recurrent miscarriages are related to immune disorders. Among them, autoimmune recurrent miscarriage is mostly seen in anti-coagulant antibody syndrome, systemic lupus erythematosus, desiccation syndrome, maternal and child blood group incompatibility, anti-sperm antibody, anti-hyaline antibody, etc. Alloimmune recurrent miscarriage is mainly due to the lack of maternal closed antibodies to protect the embryo. 11, Sperm quality, morphology, chromatin abnormalities. 12, environmental factors: environmental hormones, environmental antibiotics, radioactive substances, noise, etc. 13, bad lifestyle: smoking, alcoholism, staying up late, tight clothes, revealing the umbilical cord, etc. 14, excessive stress, tension, fear, anxiety, sadness and other adverse psychological stimuli, reduce immune function and disrupt the endocrine balance. 15, drugs: some drugs with reproductive toxicity can also cause infertility and miscarriage.