Quoting MotherFalcon~24weeks!:" is it normal to take 40mins tho? US exposure shouldnt be for that long, it can cause issues/defects with the baby the longer it is."
That's false. And yes, it can take up to 40 minutes. They have to take a lot of measurements (femur, head, abdomen, etc), plus they look at all the vital organs, take pictures of the heart, check the spine, etc.
Quoting happilymarried614:" Why do they need to measure the cervix at 20 weeks? I noticed a few other people said this too. "
Aside from measuring the cervix (just to be sure shortening or dialation isn't beginning early) , they also get a much better view w/transvag to make sure placenta isn't lying over the cervix...... atleast that is what tech told me at my appt last week.