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Determining the age of a pregnancy

Ok, so I just found out my x girlfriend is pregnant. According to her ultrasound she is 12 weeks along. The last time we had sex is June 17th, which is about 15 weeks ago. So I guess my question is how accurate is a ultra sound in determining the age of a pregnancy? Is it possible that this could be my child?

On the 17th we were on vacation and she had stoped taking her birthcontrole because she didn't get her period eight before we went in vacation.

Any help answering this question would be greatly appreciated.

thank you!
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Avatar universal
The Dr measured my sisters baby 2 weeks smaller then the baby was .. I know this cuz she knows the exact night she concieved... there is a chance that this could b ur baby :) good luck!!! I hope it is...
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Avatar universal
Sounds like you're stepping up anyway. You can still be there for her & baby regardless. Sorry that those days aren't adding up. Best of Luck!
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Avatar universal
If you love the girl raise the baby as your own! I was with my first two children's father for seven years and left and met someone else who is verbally abusive and an alcoholic and got pregnant by him and I wasn't "allowed" to be around my kids because he thought I was messing around with their dAddy! Well NOBODY is going to keep me from my children so I left and me and the girls father got back together and he is raising this baby as his own cause the idiot says that he wants to sign his rights up fine by me!!
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Avatar universal
I really wouldnt take any of these comments to heart... unless they are doctors and even then Every doctors office and doctor is different. When they do a ultrasound their saying the baby looks about 12 weeks she might a have a smaller baby... nevertheless it might be her x boyfriends I would go to a doctors appointment with her and get the answers yourself I really hope it's your baby and good luck:)
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1844152 tn?1354670990
Ultrasound and doctor's guesses are only an estimate of fetal age.
Everyone is different. If your ex doesn't
have a new boyfriend, or hasn't had sex with anyone else since January, it's without a doubt yours.
I found out I was pregnant in january, but in april, my ultrasound was estimated at 10 weeks, which is not right at all according to when I got pregnant.
Helpful - 0
202436 tn?1326474333
First of all it depends - how far along was she when they did the first ultrasound?  The further along you are the less accurate the ultrasound can be at determing the due date.  Second, is she saying she 12 weeks GESTATIONAL age or FETAL age?   Gestational age begins on the first day of her last menstrual period, so approximately two weeks before she would have actually conceived.  Fetal age begins with conception.  

another thing to consider is that sperm can live for 5-7 days in the vagina  under the proper conditions.  

Anyone can speculate, but the only way to know for certain is to have a DNA test done.  Unless she has an amnio performed during her pregnancy you will have to wait until the baby is born to do so.

If it doesn't matter to you and you plan to raise the baby then a dna test shouldn't matter.  
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1901977 tn?1333991726
Being a father isn't a matter of blood. If you want to, be the best father you can be to that child; it sounds like the baby is going to need it.
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Avatar universal
Thanks for all your help, I was actually hoping there was a way it could be mine. The guy she was seeing after we broke up is abusive and bipolar. And we have recently started dating again. Very disappointing...
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1972798 tn?1355549267
A agree with previous post about the 2 week think where drs will add 2 weeks because they go from first day of last menstrural period. 12 weeks ago was Feb 8 and if they had sex on Jan 17 sperm cant live in a body for 3 weeks. So if she is 12 weeks along but age of baby is 10 weeks old then that would put ovulation around Feb 22 and LMP around Feb 8. Hope that makes some sense.
Helpful - 0
1901977 tn?1333991726
Age or first pregnancy doesn't make a difference...was the 12 week ultrasound her first ultrasound? The earlier they are the more accurate they are. Also keep in mind that "12 weeks pregnant" means the baby was conceived about 10 weeks ago...when the doctors date us, they add on 2 weeks from conception because they date pregnancy from the last menstrual period, not when the child was actually conceived. The ultrasound shows up the same way.
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Avatar universal
This is her first pregnancy and she is 20 years old, I didn't know it that would make a difference it not....
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2031435 tn?1336008840
There not always 100% accurate. With my first they told me one thing then by the next appt they told me another weeks.
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Avatar universal
Yes January
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Avatar universal
I didn't see your entire post sorry lol
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1972798 tn?1355549267
Thats why I asked if he meant January because I looked back on calendar and January 17 was 15 weeks ago.
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Avatar universal
Hold on.. you had sex June? Its only May...
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1972798 tn?1355549267
A 3 week difference is pretty signficate. Sperm can only live inside a woman for about 3-5 days if the vaginal fluid is the correct consistancy. Meaning if she was ovulating at time of sex then the sperm would live however if not the sperm can only live a few hours.

My first thought would be to say no its not yours. However the only way to be 100% certain is a DNA test once the baby is born.

Ultrasounds these days are very acurate. If it says 12 weeks I would say she is 12 weeks along. You can ask to see a copy of the ultrasound because they will have a date on them as to how far along the measurements are showing for the baby to be. It will say 12w 2d or something like that.

Also did you mean January not June??

Hope you figure this out though. Good luck to you
Helpful - 0
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