It is difficult to determine if a pregnant woman can miscarry spontaneously within a few days if she has symptoms of pre-eclampsia, and there is individual variability. First of all, it is important to clarify whether preterm miscarriage is just a precursor sign of miscarriage, it does not mean that it will definitely miscarry. There are two different outcomes of preterm miscarriage, one is that through the treatment of birth control, the pregnancy can be restored to normal and the symptoms of preterm miscarriage will disappear. The other one is that the pregnancy is not successfully preserved and there is a spontaneous miscarriage or the embryo stops developing, or there is an indolent miscarriage. So these two different outcomes make it impossible to clarify how many days it will take for a preterm miscarriage to be spontaneously aborted. If symptoms of preterm miscarriage appear, patients must not continue to observe at home, but go to the hospital gynecological clinic for corresponding examination and treatment of fetal retention, and pay attention to the symptoms of preterm miscarriage, such as vaginal bleeding, and must pay attention to the cleanliness of the reproductive tract. In conclusion, early detection and preservation of preterm miscarriage can enable pregnant women to resume normal pregnancy, avoid overexertion in daily life and maintain a good mood.