September 1st is my due date what is my conception date? The doctor told me I conceived around the 5th to the 11th of December but I did have sex with another man but we used a condom on the 18th of November but was regularly having unprotected sex with my boyfriend. I also have short irregluare periods so I do not know my last one but I am pretty sure it was in late October. The doctor told me I was 6 weeks at my sonogram and he said he was pretty confident with my conception date he told me... do I have anything to worry about?

A due date of September 1 would put your conception date in the area of the December dates your doctor gave you. If all of your scans have kept your due date where it is currently at, baby is likely your boyfriend's. If you became pregnant from the other man, you would be a bit farther along.

Given that you used a condom and had sex just the one time with the other man, reduces the likelihood that baby is his. Could it still be possible? Sure, dates are close enough, and scans can be off a bit.

To be certain you will need to have a DNA test done after baby is born.

Can you let me know the results I'm in the same boat :(