A first-trimester ultrasound is usually done 7 to 8 weeks from the first day of your last menstrual period, says Rebecca Jackson, MD, assistant professor of obstetrics and gynecology at the Sidney Kimmel Medical College at Thomas Jefferson University in Philadelphia, PA.

How many weeks pregnant do you get your first ultrasound?

Your First Ultrasound Its typically done between 7 and 8 weeks to verify your due date, to look for a fetal heartbeat, and to measure the length of the baby from “crown to rump.” At this ultrasound, youll also learn whether youre having one baby, twins, or more!