Are ultrasound conception dates accurate?

[tina6146]

I discovered I was pregnant unexpectedly, and went to have an ultrasound on May 23rd. Due to having wavering periods, I never really keep track, and therefore I don't know when my last period was. I can give an "estimate" but I really don't know because I never keep track. (Plus I have always been told that because of metabolic issues, and PCOS that it would be very hard for me to get pregnant).
Anyway, not exactly proud of this, but I was with 2 different men in a two week time period. One I didn't use protection with on Saturday April 7th (we have been very good friends for years, and it just happened on a night out drinking/dancing) and the other man I only went out with a few times, and when we slept together the following week (on Saturday April 14th), the condom broke. I didn't think anything of it, because I am almost 38, and this has never happened to me before.
So, my question is, when I went to have my ultrasound, the sonographer did 2 measurements for the conception date: one was 6 weeks and 3 days, and the other one (just to be sure) was 6 weeks 5 days. So, we split the difference and said 6 weeks 4 days. This would make my conception date April 7th, which is the exact night I was with the first man.
Do you think there's a big chance that the 2nd man could potentially be the father? I am hoping the first man is indeed the father, because we have been friends for years, and it would be alot easier to handle. The second man, however, I don't even speak to anymore. I would hate for it to be the second man.
Any advice on people that have gone through this? I guess I just want some confirmation that these ultrasound dates are accurate. The ultrasound tech was amazing, and I feel like she really knew what she was doing, but I just want to make sure that these results couldn't be a whole 7-8 days off.

[AnnieBrooke]

Whether or not there are fertility issues from smoking, drinking and coke, the dates are on your side.  I'm glad you asked the doctor specifically about "conception" and not "how far along am I?" because the latter question would not have provided the answers you needed.

[gordosmama]

so is it possible to get pregnant 4 days before your period and miss it or was i pregnant prior to that date?

[Kirstie_MHModerator]

The best way to get feedback is by starting your own thread.  You can go back to the main board here:
http://www.medhelp.org/forums/DNA---Paternity/show/1492
Then click the "post a question" button at the top of the page.

[Sophia75]

Ok thanks...can u remove my post from this topic pls?

[Kirstie_MHModerator]

Done!

[pleasehelp709]

After having 3 ultrasounds my doctor as well as the ultrasound tech said i am 20 weeks today and my due date is July 4th. When i count back 40 weeks from July 4th it falls on September 29th. My now boyfriend and I had sex for the first time on October 1st while as gross as it sounds, was still on my period. We continued having sex multiple times throughout the next couple weeks but he always pulled out. I also slept with someone else on October 11th. Based on the ''conception calculator'' i conceived on the 11th or sometime before or after. I know ultrasounds are only 3 to 5 days off which would make it my boyfriends. However i get confused with the conception calculator telling me differently. Can someone please help me with this!