How accurate is my due date when both my 8 week ultrasound and my 12 week ultrasound have the same date ?

Pregnancy due date: The most accurate way of estimating the age of your pregnancy is the date if your last period if you are consistently regular. If you are irregular the us is a good estimate but may differ by 1-3 wks in most cases depending on the period( 1st, 2nd or 3rd trimester) it is performed. Your OB provider should be able to give you a good estimate on that.