Do ultrasounds go by your lmp as well?

Ultrasounds go by the measurements of the baby, not by the LMP. Just remember, though, that pregnancy is a guessing game. We guess as to when baby was conceived by the LMP, however, some women do have a period in early pregnancy. We guess as to baby's gestational age with the measurements of the ultrasound, but some babies are bigger or smaller than others.

We are never 100% sure of when Mom conceived.

YES I got a scan today and it clearly states at the bottom GA LMP which means age from last period. So they date the pregnancy before you are pregnant.