How accurate is an ultra sound at figuring out the due date and week of baby?

Ooooh...that's a crappy problem! Ultrasounds are quite accurate - the earlier they are, the more accurate they are. I had an ultrasound at 10 weeks and I got my due date from that... I vote guy B. :)

If you are pregnant and see your doctor, give her all that information and she will be able to help you out.

I would say guy a, but you can never be sure. We all ovulate at different times during different cycles and sperm can live a few days. Depending on when you expected your period, if you count backwards 14 days, that should eb about when you got pregnant. I have a similar situation, I'm 30 weeks now and just have to wait for a paternity test after the baby is born. Good luck!

By just looking at dates, I'd say Guy A. Sounds like Guy B was right before your period was due (tho that's no gntee, as we know). Plus, the bit about protection throws in a bit of uncertainty, eh?!

My bet is still on Guy A, if it's anyone at all.

I hope you get the result you're looking for, whatever that may be.

Best to you.

The earlier you get an ultrasound the more accurate it is. The first weeks an ultrasound can be extremely accurate because eggs that turn into embryos and so forth happen at relatively the same pace and they can pinpoint by the amount of growth that has occurred so far.