Level 1: When should B-ultrasound be done in early pregnancy? In the early stages of pregnancy, B-ultrasound is one of the most important examination methods. So, when is the appropriate time to have a B-ultrasound? Generally speaking, it is recommended to have the first B-ultrasound examination around 7-8 weeks of pregnancy. At this point in time, the development of the fetus can already be clarified, and whether there are abnormalities such as ectopic pregnancy can be determined. If you need to further observe the development of the fetus, you can do so around 11-14 weeks of pregnancy.