Yes always go by ultrasound for due date.
So the ultrasound is more accurate than going by LMP?
They'll also use ultrasound measurements to help determine due date
So the ultrasound is very accurate cause they were going by my LMP which was 1/30 and lasted 2 days and did the ultrasound and the measurements were more weeks than LMP
Ovulation happens in the middle of your cycle usually, so on the date of conception they will say you are a couple weeks along because of your cycle. That's why they go by last monthly period when giving estimated due date
You're technically pregnant every month because your body is preparing for a fertilized egg, then when it doesn't happen you get a period. So the first 2 weeks is the thickening of the uterine lining and the release of the egg. Then around week 3-4 it attaches and starts forming a baby. Around weeks 4-5 is when u test positive.