The most common clinical cause of vaginal redness after the second trimester is preterm miscarriage. It is recommended to have an ultrasound examination as soon as possible to find out if the embryo is still developing normally in the uterus. If the usual menstrual cycle is 28-30 days/period, the primitive heart can be seen by ultrasound in the second month of pregnancy. If the primitive heart tube is still not visible, it is possible that the embryo has stopped developing. It is recommended to analyze the clinical situation together with the time of the last menstrual period, the blood HCG monitoring and the progesterone test. If the embryo is developing well, continue to give fetal preservation treatment and rest in bed, but if it has stopped developing, terminate the pregnancy as soon as possible.