The birth control injection has the effect of preserving the fetus, but it does not guarantee that the fetus will be preserved. The most common cause of miscarriage is poor embryonic development. The most common causes of miscarriage are poor embryonic development, poor rest, and environmental factors. If the embryo is underdeveloped, the progesterone is particularly low, or the HCG is not doubled, the probability of success in this type of preterm miscarriage is very low. If the bleeding is only slight and all other test indicators are normal, the probability of success in this type of preterm miscarriage is obviously increased. Therefore, in the early stage of pregnancy, if you need to keep the pregnancy, you should keep the pregnancy and observe at the same time, the early stage of pregnancy itself is the process of superiority and inferiority.