Understanding Pregnancy Dating & Ultrasound Accuracy: A Doctor's Explanation

Question
I don't know when my last period was and so this past two weeks I thought that I was about to start then this past week My boobs were sore and felt nausiated for three days.  Had an ultrs sound and he said that I am 14wks   but then my obgyn says he told her I was 12wks and 6 days whoch makes it 13wks tomorrow and he said due date would be feb 25.  How accurate is that machine with the measurments he checked and punched in?


Answer
Hi Tiffany,

The ultrasound isn't as accurate as knowing the date of your last period, however, when you don't know, ultrasound is pretty accurate give or take a week or so.  So, I would be pretty confident that you are around 13 weeks or so.  Good luck!