how can this be?

[cbabylove]

So my lmp was on April 17,2013 thats the exact date im sure and I missed my period the next month and from that date I got a due date of January 22 2014. I had a ultrasound on 7.02.13 giving me a due date of January 28 2014 putting me at 10 wks 6 days. How can this be. I made mistake and kinda cheated on my boyfriend on may 7 2013 but no sperm was ever expelled because he was in me for about a minute..can the guy from may 7 be the father ? And could the ultrasound tech be wrong about my due date ?

[AnnieBrooke]

Dates counted backwards from an estimated due date given to you from an early ultrasound, are always more reliable than dates counting forward from the first day of your last period.  But the ultrasound has to be early in the pregnancy (by the 12th week, some doctors will give a margin for error of 7 days or more).  

If a woman has irregular periods, she could ovulate a little late or a little early in her cycle, and then an app that simply counts forward from the first day of the last period, and assumes two weeks to ovulation, would not be reliable.  So, that's how it could happen.  

But you had your ultrasound at almost 11 weeks.  This would mean the ultrasound dating might have a +/- of at least a few days, either direction.  It could be spot on, if your baby grows at the average rate, but some babies grow faster or slower than normal.  

Remembering that you do have a margin for error of a few days, here is what the conception calculator I use says about the due date of January 28.

     Probable date of ovulation:  May 7
     Possible dates of conception:  May 3 to 11
     Due date:  January 28 (40 weeks)

I'm assuming the sex with your boyfriend continued through this same time period?  And that the sex with both guys was unprotected?  Even with the brief encounter that you described, it's not impossible for the second guy to be the dad.  If you were having lots of unprotected sex with your boyfriend during the same time period, he is likelier to be the father, but you're still going to need to do a DNA test when the baby is born.  Even if the first projection you did had been correct (of a due date 6 days earlier) it is still a very close thing and I would recommend doing a DNA test in that case too.  But especially you need to, since the two guys might have had sperm in your system at the same time.  

[asmith21488]

Even a drop of precum can cause it...idk bout the rest