Even dating scans can be inaccurate for the due date, but they are never as inaccurate as using the menstrual period. For instance a dating scan done at 6 weeks could get the date wrong five days either way.

Why does scan change due date?

“The ultrasound in the first trimester is the most accurate for determining due date because we use a crown to rump length,” she says. An early second trimester ultrasound may also change your due date if you didnt have a first trimester ultrasound, Greves says.

Is it normal to feel movement in your stomach when your not pregnant?

Its possible to have sensations that feel like a baby kicking when you arent pregnant. Several normal movements in a womans body can mimic a babys kicks. This includes gas, muscle contractions, and peristalsis—the wave-like motions of intestinal digestion. Women often refer to the sensation as phantom kicks.