After natural or artificial conception (including artificial insemination and in vitro fertilization), if the fetus is less than 28 weeks pregnant and does not have the ability to survive on its own, it is called miscarriage. Spontaneous miscarriage occurs before 12 weeks as early miscarriage and between 12 and 28 weeks as late miscarriage. In our clinic, we found that many pregnant mothers are very careful after pregnancy, some of them are on bed rest, but they still miscarried “strangely”, and some of them have miscarried once, but unfortunately, they miscarried again. Why is this? In fact, the most common cause of early miscarriage is a defect in the fertilized egg itself, a process of natural selection, while late miscarriage is often related to maternal abnormalities. What are the common causes of spontaneous miscarriage? 1, embryonic chromosomal abnormalities: common causes of fetal chromosomal abnormalities are: one is chromosomal abnormalities in one or both parents of the fetus, chromosomal abnormal carriers, for example: Robinson equilibrium ectopic carriers, normal phenotype, but a genotype, the embryo conceived has a high chance of being an abnormal embryo, resulting in embryonic developmental disorders, resulting in miscarriage. Secondly, there are teratogenic factors in the environment, including radiation, viruses, drugs and other factors acting on sperm, eggs or fertilized eggs, resulting in fetal chromosomal abnormalities. The most common chromosomal abnormalities in miscarried children are: trisomy 16, X monosomy, trisomy 13, trisomy 18, etc. 2, maternal factors: endocrine abnormalities, such as luteal insufficiency, polycystic ovary syndrome, diabetes, hyperthyroidism or hypothyroidism, obesity, etc.; immune abnormalities; uterine organ abnormalities; infections; bad habits, such as smoking, alcoholism, coffee, etc. Abnormalities of female reproductive organs include uterine fibroids, uterine longitudinal septum, uterine cavity adhesions, endocervical laxity, endometritis, etc., all of which are associated with spontaneous abortion. Loose endocervical opening tends to lead to miscarriage in the middle of pregnancy (around 5 months). Most women with uterine cavity adhesions have a history of multiple abortions, resulting in severe damage to the endometrium and adhesions that shrink and deform the uterine cavity and sclerosis of the endometrium that affects embryo development. Infection with virus, bacteria, parasites or mold before or during pregnancy, or inflammation of the fallopian tubes or endometrium can also easily lead to miscarriage. Therefore, it is recommended that pregnant women preparing for pregnancy undergo eugenics testing, including TORCH, etc. Endocrine abnormalities in pregnant women: for example, high androgens and high prolactin can lead to infertility and miscarriage; insufficient luteal function, which makes the endometrium secrete poorly, can also lead to miscarriage. In addition, thyroid disease, diabetes is also a possible cause of miscarriage. 3, environmental factors: such as work or living environment exposure to excessive exposure to benzene, formaldehyde, lead, ion radiation, etc. Immune abnormalities: Current research has found that miscarriage is closely related to immune factors, pregnancy is in a way the process of the body to accommodate a “foreign body”, if the body thinks that the embryo is a “bad thing”, so use the immune system to embryo to start If the body thinks that the embryo is a “bad thing”, it uses its immune system to “attack” the embryo and expels it as a foreign body. So far, obstetricians and gynecologists believe that it is difficult to find objective evidence of the cause of such miscarriages, the treatment cannot be unified, and the results of treatment vary from report to report, which is a difficult problem. 4, abnormal sperm quality: men in long-term high temperature, radiation environment, or alcohol, smoking, etc., resulting in a decline in sperm quality, resulting in abnormal fertilized eggs, resulting in miscarriage. 5, pregnant women combined with other systemic diseases: when pregnant women suffer from acute infectious diseases such as influenza, typhoid, pneumonia, bacterial toxins or viruses enter the fetus through the placenta, which can cause fetal poisoning and death. High fever can promote uterine contraction and cause miscarriage. When a pregnant woman suffers from chronic diseases such as severe anemia, heart failure, nephritis and hypertension, the fetus can be affected by placental infarction and lack of oxygen in the uterus, resulting in miscarriage.