due date error?

[eekax3]

I need help . my lmp was sept. 15th which means I would have ovulated oct 2nd based on my calculations. which means I would have a due date of June 22nd and I was 11 weeks and 4 days pregnant. my first ultrasound said that I was actually 10 weeks an 4 days pregnant leaving me with a due date of June 30th by the measurement of the baby. but that couldn't be possible because that would mean I would have had my period on sept. 21st and ovulated on oct. 6th or 7th I forget , either way that's impossible because I know exactly when my last period was. when do you think I conceived and/or ovulated? I'm so confused at this point . please help me . also I have a 31 day cycle not 28. thank you!

[AnnieBrooke]

You said, "my first ultrasound said that I was actually 10 weeks an 4 days pregnant leaving me with a due date of June 30th by the measurement of the baby. but that couldn't be possible because that would mean I would have had my period on sept. 21st and ovulated on oct. 6th or 7th I forget , either way that's impossible because I know exactly when my last period was."  However, women can ovulate at quite a range within their cycle, it's not always two weeks after the first day of their last period.  So when your last period began is not as important as getting the exact measurements of the baby in an early ultrasound.  If the measurements of the baby suggest it was conceived on a certain day, such as October 7, it doesn't really matter when your period began.  The computation an ultrasound uses to project back and say your first day of your last period is simply a pretty automatic two week margin, but the measurement of the baby is exact, at least until you get later in the pregnancy.  

However, your problem is that you didn't have a super-early ultrasound, and some babies grow faster or slower than the average.  If you had had an ultrasound at 6 or 7 weeks, then you might be able to hope it would be pinpoint in accuracy for determining dating, but by your tenth week, there is a margin for error possible of at least a few days.

I'd say you're pretty stuck, the guys are just too close together, you're going to need a DNA test to sort this one out.  I'm sorry.

[eekax3]

yeah they are regular . the first guy has a hernia and had it since he was born. does that matter any?

[AnnieBrooke]

Unfortunately, with that due date, the calculator I use gives October 3 - 11 as the possible dates of conception.  Are your periods always super regular?  Because it is not entirely accurate to count forward from your last period, it's more accurate to count backward from your estimated due date, if it was given to you by an ultrasound measurement.  Ovulation can happen almost any time in your cycle.

[eekax3]

I should add that I had sex with a guy on sept 30,31&oct 1,2,3 and never used a condom just pulled out but he has a lot of precum and had sex with another guy October 5th but we used a condom once and pulled out the second time in one night. please don't judge..no rude comments please I just need help figuring this out.