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Avatar universal

Dates don't add up

My boyfriend of 9 years and I broke up last October and slept with a girl who is now pregnant. He swears he wore a condom but went along with it at first bc she insisted it was his. He slept with her the night of oct 14th and her due date is June 28th 2015. Which doesn't add up. We know now that she was sleeping with at least one other person during this time period and living with the father of her 2 yr old daughter, with which she claims she hasn't slept with in a long time. She claims it is my boyfriends baby bc the other guy "never came". Everything I loook up shows that she would've already been pregnant by the time she slept with my boyfriend but didn't know it yet. It's dausing a lot of stress in our relationship and I need to know how reliable her due date could be. She sent him a picture of an ultrasound January 9th saying she was 15 weeks 5 days
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134578 tn?1693250592
COMMUNITY LEADER
It is interesting that you have read that ultrasounds only have a margin for error of three days as late as 15 weeks.  I've heard from numerous people on this site who had been told by their doctors that at 12 weeks there is a margin for error of +/- 7 days or more.  Several times they have quoted this from their ultrasound reports.

Anyway, unless you are going to the appointments with her and sitting in while the doctor does the ultrasound analysis, there really is no way to know.  It doesn't sound like your boyfriend's baby, unless something about the dates he had sex with her are not what he told you.  But it does sound close enough that a DNA test is necessary to know for sure.
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Avatar universal
But I think she used the date of her last period at the first appt and then they did the ultrasound at her 2nd appt and compared....
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Avatar universal
I believe at that point she was 13 weeks and a few days...I've read that up until about 15 weeks, ultrasounds are pretty precise give or take 3 days. With his situation there is a 9-10 day difference....
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134578 tn?1693250592
COMMUNITY LEADER
If the ultrasound was from her sixth or seventh week (counted from the first day of her last period), he could stop worrying so much that the baby is his, because the estimated conception date from her due date does not line up with when he [says he] had sex with her.  But if her first scan was not until a few weeks later than December 3, that sounds too late for certainty in determining an exact conception date.  Do you know how many weeks and days she was at the time she had her first scan?
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Avatar universal
She had originally confirmed pregnancy dec 3rd at the dr and had her first scan a few weeks later
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134578 tn?1693250592
COMMUNITY LEADER
The dates make it sound  like the baby was conceived around October 4 or 5.  How early did she get the dates?  An ultrasound in the 15th week can have a pretty big margin for error if someone is trying to use it to determine paternity.
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