Concerned Mother

[aprilclark]

My son's girlfriend is pregnant, the first time they had sex was September 11, 2008. She had an ultrasound they determined that she is 8 weeks ans 2 days.  My question is ..How accurate is an ultrasound can it be off by as much as a week or two? This date makes us question the paturnity of this child.

[spinis]

It is possible. The way they measure how far along you are is from the last time you had your period. So, from Sept 11 until know there are 6 weeks + another 2 (if she has a regular cycle and ovulates in the middle of it (after 2 weeks). It's about 8 weeks.
Ultrasounds also have errors- few days. It's all estimation. So it is possible...

[cantwait4baby]

I conceived on September 22nd and i am today 7 weeks.  Sounds right to me.

[nsrchofbaby]

Hi April,
There are actually a lot of things that go into trying to pinpoint time of conception...now assuming your son's gf ovulated and got pregnant the first time they had sex, and assuming that she has a normal 28 day cycle, I would think that her LMP (last menstrual period) was on or around August 28th....we would then count the weeks from that day and she would be approx 9 weeks along today. Again, that is assuming everything happened based on this timing and scenario. It is definitely possible that she ovulated later or that she got pregnant during any episode after Sept 11th. So I would say that the US dates of 8 wks 2 days is VERY plausible. Even so, if you have any doubts about the paternity of the child, only a DNA test will give you the answers that you seek. I wish you the best of luck. Take care and God Bless.