A miscarriage is a termination of pregnancy at less than 28 weeks, or a fetus of less than 1000g, and is called a miscarriage. If a normal couple has one spontaneous miscarriage, there is no need to be too nervous, as the rate of spontaneous miscarriage is also 20% under normal circumstances, which is the result of natural selection and the survival of the fittest. Those who have had 2 or more consecutive spontaneous abortions, excluding biochemical pregnancies, are called recurrent abortions. The effects of each miscarriage can affect the chances of increasing the next pregnancy. In this case, it is necessary for the couple to examine the cause of recurrent miscarriage, and to make targeted treatment for the cause of miscarriage before another pregnancy. For the diagnosis of recurrent miscarriage, there is no unified standard diagnostic process, which is also because the etiology of recurrent miscarriage is extremely complex and there are many causes of recurrent miscarriage. 1. genetic factors: spontaneous miscarriage caused by abnormalities in one or both spouses or embryonic chromosomes, which is the main cause of spontaneous miscarriage; 2. anatomical factors: miscarriage caused by factors such as abnormal uterine development, mainly including: congenital uterine malformation, uterine fibroids, cervical insufficiency, uterine adhesions, etc.; 3. immune-related factors: such as autoimmune diseases, including systemic lupus erythematosus, antiphospholipid antibody syndrome, etc.; 4, endocrine factors: luteal insufficiency or autoimmunity or alloimmunity caused by various endocrine factors can lead to recurrent miscarriage; 5, unwanted habits, such as smoking, drinking alcohol, drinking strong tea, etc. are environmental factors that cause miscarriage.