A 6 week ultrasound is not a common ultrasound, but there are a plenty of reasons that a 6 week ultrasound will be requested by a medical professional. The most popular reasons that a 6 week ultrasound will occur is because the mother has had pregnancy complications or pregnancy losses in the past. Another reason to get an early ultrasound would be due to the age or specific medical history of the mother. Some things that a 6 week ultrasound will reveal would be the heartbeat of the fetus, the number of present fetuses (twins or more!), the location of the ultrasound, and the shape and status of the yolk sac for the fetus.