It’s what my ultrasound tech told me. I am sure there are outliers, of course, but very early ultrasounds are pretty good.
Ive had them for dating a pregnancy, investigating miscarriages or potential miscarriages, and for tracking down a wayward IUD. Like MandaJo says, they’re not that big a deal, but that doesn’t mean they should ever be mandated.
Edward, here’s an article that addresses the accuracy of ultrasounds for early pregnancy dating: New charts for ultrasound dating of pregnancy and assessment of fetal growth: longitudinal data from a population-based cohort study - PubMed