A fetus with preterm miscarriage is not necessarily malformed. In clinical terms, preeclampsia is defined as a small amount of vaginal bleeding without discharge of the pregnancy, followed by pain in the lower abdomen before the 28th week of pregnancy. Gynecological examination of the cervix is not open and the fetal membranes are not ruptured. After rest and treatment, the symptoms disappear and the pregnancy can continue. However, in some cases, the symptoms worsen and develop into inevitable miscarriage. The causes of preeclampsia are complex and mainly include embryonic factors, parental factors and psychosocial factors. Embryonic factors are mainly chromosomal abnormalities of the embryo or fetus (abnormal chromosome number or abnormal chromosome structure). Parental factors include female endocrine function abnormalities (such as luteal insufficiency, thyroid function abnormalities, etc.), parents’ bad habits (such as smoking, alcoholism, etc.), uterine diseases (uterine abnormalities, cervical insufficiency, uterine fibroids, etc.), and other diseases suffered by the pregnant woman (severe anemia, systemic lupus erythematosus, chronic liver and renal diseases, viral, bacterial, and parasitic infections, etc.). In addition, pregnant women experiencing intense stress or psychological overstress, anxiety, fear, sadness, etc. can lead to miscarriage, as well as overwork in life, excessive exposure to radiation and harmful chemicals. The causes of preterm miscarriage are complex, and the mere presence of preterm miscarriage does not mean that the fetus will have abnormalities. Pregnant women do not need to be too anxious.