Pre-eclampsia can occur within 28 weeks of pregnancy. If a small amount of vaginal bleeding or bloody leukorrhea occurs during the 28th week of pregnancy, with no detectable expulsion of pregnancy tissue, and is accompanied by bouts of abdominal pain and lower back pain, there is a possibility of a preeclamptic miscarriage. Pre-eclampsia may occur at any time during the 28 weeks of pregnancy. Some pregnant women experience pre-eclampsia around 35 days after their last menstrual period, when the fertilized egg has successfully implanted, and may present with symptoms of a small amount of vaginal bleeding, but not abdominal pain. After the symptoms of preterm miscarriage are detected, pregnant women need to go to the hospital in time for HCG, ultrasound and other tests, as well as treatment to preserve the pregnancy.