The rate of preservation of preterm miscarriage is determined according to the causes leading to preterm miscarriage, as follows: 1. Higher: If the preterm miscarriage is caused by low progesterone, or unexpected stimulation, the success of preservation is relatively high, and the chance of success can reach more than 90%. 2. Lower: If the preterm miscarriage is caused by embryonic dysplasia, or chromosomal abnormality, etc., it is a kind of superior process. The success rate of fetal preservation will not be very high, even if the early preservation is successful, the fetal malformation will be found in the later screening examination and need to be induced for abortion treatment. Therefore, once the symptoms of pre-eclampsia miscarriage appear, you should not blindly carry out birth control, but go to the hospital for relevant examinations to determine whether it is caused by low progesterone, and if it is caused by low progesterone, the symptoms of abdominal pain and vaginal bleeding will improve after appropriate oral or inotropic progesterone is given, and after successful birth control, the number of pregnancy tests should be increased appropriately, and regular teratological examinations should be carried out.