Fetal abortion can occur at all stages of pregnancy, but it is generally more likely to occur around 6-10 weeks of pregnancy and less likely to occur after 12 weeks of pregnancy. There are many causes of fetal abortion, most of them are related to the abnormalities of the embryo itself, and some of them are related to luteal insufficiency, hyperprolactinemia, abnormal thyroid function, diabetes and autoimmune diseases. In the case of fetal arrest, it can be manifested as abdominal pain, vaginal bleeding, disappearance of early pregnancy response, disappearance of nausea and vomiting, and shrinkage of the uterus instead of enlargement. Most pregnant women have no obvious symptoms after fetal arrest, and need to be clearly diagnosed by hormonal examination and early pregnancy ultrasound. If there is no gestational sac at 6 weeks after ultrasound examination, or if there is a gestational sac but it is deformed and shrunken, or if the gestational sac is ≥2.5cm and no fetal bud is visible, and there is no fetal heartbeat on vaginal ultrasound, embryonic abortion can be determined. If the fetus is ≥5 weeks and the blood β-HCG is <100IU/L, or if the fetus is ≥6 weeks and the blood β-HCG is <2000IU/L, it often indicates that the chorionic gonadotropin secretion is insufficient, and if the HCG value is no longer rising by dynamic observation, it can be determined that the chorionic epithelium is declining and the embryo is abnormal. Once fetal abortion is detected, the pregnancy needs to be terminated promptly according to the situation.