Ultrasound at 8 weeks of pregnancy is generally accurate in showing cessation of embryonic development because it can monitor the fetal heartbeat, and if it shows cessation of the fetal heartbeat after it was previously observable, it indicates cessation of fetal development, and can be combined with other laboratory tests such as blood HCG (human chorionic gonadotropin). In early pregnancy, i.e. the first trimester, the growth of the fetus is unstable and may stop due to chromosomal abnormalities, medications, radiation, etc. Ultrasound is a more accurate means of detecting this phenomenon, and blood HCG (human chorionic gonadotropin) levels can also be tested to see if there is a significant drop to make a judgment. If embryonic arrest occurs at 8 weeks of pregnancy, it is recommended that you go to the hospital in time to have the uterus cleared to prevent the arrested fetus from staying in the uterus for too long and causing an infection in the uterus.