How do they measure/weigh baby in womb?

[ouiouiouioui]

I'm getting the old "large for gestational age" scan results/concerns.

How are they measuring baby in the womb?

You've seen them do it, surely. They use a tool onscreen to measure the scan image.

Weights are estimated based on measurements and can be very off. You don't actually know what a baby weighs until it's out.