Any chance i am the father?

[ArgonautTim]

I had sex with a friend on the night of july 12/13. I learned she became pregnant after she posted a picture of her ultrasound. The ultrasound was dated to be done on October 20th and said she was 12weeks and 3 days pregnant. I'm uncertain about her cycle length and i've also heard that ultrasound dating can be off from 7-10 days.

Can anyone shed some light? She's assured me that i'm not the father but I wanted to be sure.

[AnnieBrooke]

No, it does not look like you're the dad. Count it out on a calendar as 10 weeks 3 days from conception as of the date of the ultrasound. (The GA count, the 12 weeks 3 days figure, is counted from her first day of her last period, not from conception.) It should ease your mind.

[ArgonautTim]

When an ultrasound calculates GA does it always add 2 weeks from possible conception date to get the date of the last period?

My biggest concern right now is that the ultrasound is off by 10 days which would put her last period on July 15th, and since we had sex on the night of the 12th going into the 13th, with sperm being able to survive 5 days, that conception occurred.

Is this a possibility to even consider or is it unlikely and I am I just over analyzing this. These thoughts have been keeping me up at night and I'd really like to put it all to rest.

[AnnieBrooke]

1) GA is calculated from the assumed first day of last period, which is two weeks before conception.
2) The pregnant woman is not telling you that you are the dad and is not telling you that you need to take a DNA test. That's usually a big clue. If a woman has any doubts, she will tell you that you should be ready to do a test.