Ultrasound Conception Date Accuracy: Is it Reliable?

Question
Hello. I was with my girlfriend on march 14th, she was with her ex on the 23rd. she is pregnant. she had an ultrasound done within the first trimester, I believe 6-9 weeks in, and the given conception date was march 20th. From what Ive read conception date accuracy if done within the first trimester is very accurate. the doctors she saw said that the date was accurate within 1-2 days. is this so? could she have gotten pregnant on the 23rd? There will be a paternity test no doubt, I would just like to know what your thoughts are about ultrasound conception dates and who do you think is more likely the father.

Answer
Adam,

You're correct that early ultrasound is quite accurate, typically within +/- 3 days (it depends upon the equipment used & the skill of the technician).


So it's still entirely possible that she conceived on the 23rd.   If I had to pick, I'd say you were much more likely to be the father.



Best,
Catherine