Ectopic pregnancy and biochemical pregnancy can be determined by the difference between ultrasound and clinical symptoms. 1. Ultrasound: biochemical pregnancy is usually only a transient elevation of blood HCG (human chorionic gonadotropin), ultrasound will not find anything inside or outside the uterus or just accompanied by thickening of the uterine lining; ectopic pregnancy is usually accompanied by an elevation of HCG, but in the uterus outside the mass will be seen. 2. Clinical symptoms: biochemical pregnancy is generally like a menstrual period, and there are no other symptoms; ectopic pregnancy may be accompanied by abdominal pain, abnormal spotting bleeding, and in severe cases, hemorrhagic shock may also occur. So if you are sure that you are pregnant and have an abnormal performance, then it is recommended that you consult a doctor in time to treat the symptoms.