A common possible situation that women often face in pregnancy is spontaneous abortion, the incidence of which, according to statistics, varies from about 10-15%. In order to prevent spontaneous abortion, it is important to first identify the causes of spontaneous abortion and to intervene and treat the causes in order to target them. First of all, let’s clarify the definition of spontaneous abortion, which includes spontaneous abortion and induced abortion. Spontaneous abortion is the abortion of an embryo by itself without human intervention. Spontaneous abortion is the natural abortion of the embryo before 28 weeks of gestation. The most common causes of natural miscarriage are 1, the most common and important is the embryo chromosomal problems, is also on the genetic problems, this situation embryo often can not develop normally, will only develop into a normal embryo, in the process of development will naturally die, and then cause natural miscarriage, this situation accounts for the general causes of natural miscarriage above. 2, hormone level abnormal, mainly the luteal function is insufficient to support the development of the embryo, mainly manifested as low progesterone, hcg rise more slowly. 3, abnormal uterine anatomical factors, congenital uterine development abnormalities, such as longitudinal uterus, unicornuate uterus, saddle-shaped uterus, etc., affect the development of embryo in the uterus, resulting in spontaneous abortion of embryo 4, infection factors of the body: various types of infections (respiratory and reproductive tract infections), including TORCH, may also cause spontaneous abortion. 5.Immune factors: mainly including rheumatic series and autoimmune antibody series, the body treats the gestational sac as a foreign body and launches an immune rejection reaction, which in turn causes spontaneous abortion. 6, other factors: spontaneous miscarriage is related to many other undesirable factors, such as exposure to harmful substances, radiation exposure, etc.; it also includes psychological factors, such as mental tension, depression, fear, sadness, etc.; excessive physical labor, smoking, alcoholism, excessive coffee, drug abuse and other bad habits. If a spontaneous miscarriage occurs, do not be too nervous, too sad, as far as possible, according to the above-mentioned situation to find the causes of spontaneous miscarriage, targeted intervention for the causes, if really can not find the cause, do not be nervous, generally a spontaneous miscarriage there are many incidental hidden go, the next pregnancy when the serious preparation, careful maternity examination, generally will be subject to a good outcome.