Ectopic pregnancy is the common name for ectopic pregnancy. When the location cannot be detected by ultrasound, the ultrasound should be checked regularly and the blood HCG (human chorionic gonadotropin) should be detected, which may be due to the short time of conception before the ultrasound can detect the pregnancy; and there is also the possibility that it is an abdominal pregnancy. 1. Short time of conception: If the time of conception is too short, the embryo is too small to be detected by ultrasound, so even ultrasound can not detect its position, and ultrasound should be reviewed regularly, and if necessary, transvaginal ultrasound. 2. Abdominal pregnancy: because the fertilized egg is deposited in the abdominal cavity, and the abdominal cavity and the intestinal tubes are constantly peristalsis, so the ultrasound examination can affect the field of vision, so the ultrasound may not be able to detect the location of the embryo, then we need to dynamically observe the changes in the blood HCG, and if necessary, carry out a cesarean section. Ectopic pregnancy means that the fertilized egg is deposited in a place other than the uterine cavity. The most common site is the fallopian tube. When the pregnancy is confirmed by blood HCG examination, but there is no pregnancy material in the intrauterine and adnexal area by ultrasonography, the negative ultrasonography should be reviewed periodically, and caesarean section should be performed if necessary.