Ultrasound accuracy? Conception? 2 possible fathers!

[Soon2be]

So I'm 33 weeks pregnant right now. I know exact dates of my LMP it was August 28th 2008. I had sex (with my partner ejaculating) on September 9h,10th,16th, and 20th. On September 7th I was with someone else and this guy penetrated me for about 3 minutes but I told him to stop. During the incident, the guy was hard but we weren't fooling around, and I know for sure I did see the clear pre eja fluid on his penis though. He got out of me when I told him to stop and there was penetrtion for less than 3 minutes. My period was due in on September 25th 2008. I took a pregnancy test about 4 days after and it was negative. So again I took one Ocotber 1st. Still negative. well finally 13 days after my missed period on Ocotber 7th I got a faint positive. I got a blood test and my HGC levels were very low. Well about a week later they came back that they were indeed going up. i had an ultrasound on October 12th that said my due date was June 14th 2009...but based on my lmp I was due on June 4th. Being my ultrasound was at 7 weeks he said he was going with the ultrasound due date. Which would put ovulation and conception around September 17-22. Well I had another ultrasound at 14 weeks from anouther doctor and a different machine that dated me at June 14th.
So, how likely is it that the Sept. 7th quick
penetration got me pregnant? How accurate are ultrasounds? Could the U/S be wrong...I had a perfect 28 day cycle so based on that it would be the guy who was only 3 minutes..Being my lmp was august 28. This descrepency is causing me a very emotionally painful pregnancy and I would very much appreciate input. It just doesn't seem logical that someone who stuck it in and pulled it out could have gotten me pregnant. Although like I said I did see the pre eja fluid on his penis. Please some input. IIM PULLING MY HAIR OUT! =(

[GermanBaby]

I know "life" happens and in no way am I judging you. You are the one who knows what you can live with or what will enable you to sleep at night. If your current partner believes that he is the father and will be supporting you and/or the baby emotionally, and physically and financially no matter what then you must decide if being "honest" would be doing more harm then good. Yes you did not "cheat" but this is obviously "bothering" you. If you truely believe with your heart that this baby IS your current partner then let it be. But if you have doubts - these doubts will affect your relationship at some level (conscious or otherwise) and your current partner may pick up that something is "wrong". What if in the future some "tests" were required and it turned out that the child was not his and he found out you had "doubts" when the baby was concieved and did not tell him then? That is the risk you will have to take. That being said there are many cases in history expecially with the Royal Families in many countries where it is doubtful the King was the biological father but the child became Royalty anyways:-) I do believe that "A women's heart is an Ocean full of secrets" you are the one who knows which ones you can live with. Just my opinion - Good Luck :-) Whatever you decide is the right answer.

[Soon2be]

I have not been honest with him....Just because I didnt cheat on him..this happened when were wernt together and then we got back together. But as for me stressing out I have realized you can not change yesterday. and having such a negative thought on this is not going to change anything nor make it better. So im starting to have faith that it will work out in my favor. Ihave learned a 100% lesson from this and im a whole new changed person. And who knows..if hes the dad then maybe this was my "scare" that I needed to change my life. Which it has done..so right now im just having faith in it. Life happenes u know...it does..im just glad ive really learned from this.

[Soon2be]

I have not been honest with him....Just because I didnt cheat on him..this happened when were wernt together and then we got back together. But as for me stressing out I have realized you can not change yesterday. and having such a negative thought on this is not going to change anything nor make it better. So im starting to have faith that it will work out in my favor. Ihave learned a 100% lesson from this and im a whole new changed person. And who knows..if hes the dad then maybe this was my "scare" that I needed to change my life. Which it has done..so right now im just having faith in it. Life happenes u know...it does..im just glad ive really learned from this.

[mima09]

According to your LMP it seems like you should be do June 5th...I would stick with LMP.....my daughter had the ultrasound done at 7 weeks and i don't care what they say, they grow different then too...go on I am pregnant and look at all the ultrasounds at 7weeks and 9 weeks, very different looking...I think you ovulated around Sept. 10th.  I bet your partner is the father.....Good luck and try not to stress to much, whatever is to be will be....

[nsrchofbaby]

I agree that the probability of your current partner being the father is greater but only a DNA test will give you a definitive answer. There's no getting around it. Pre-ejaculate can empregnate a woman. The fact that there are less than 2 wks difference between the first and last encounter doesn't bode well either. Ultrasounds are said to be very accurate when done early on in a pregnancy but should never replace an actual DNA test when trying to determine paternity. Good luck, I truly hope you find the answers you're looking for once this child is born.

[GermanBaby]

The earlier ultrasound should be the more accurate one as during the pregnancy the babys growth will vary depending on the exposure to placental hormones and nutritients.

My LMP was Sept 11 and I know I conceived 2 weeks later - my date was June 19. All earlier ultrasounds confirmed this. However just last week my doctor said my new date is June 10.

I think the best thing is to be honest with your current partner - if you have not already. You should not be going through this emotional anxiety alone. Anything is a possibility but the likelyhood of your "current" partner being the father seems more real.