Ultrasound Accuracy

[girly18]

What is the accuracy of an abdominal ultrasound at 11 weeks? Is there a difference between abdominal & transvaginal ultrasounds in regard to accuracy?

[AnnieBrooke]

It happens.  We get a lot of posters on this forum whose dates really don't add up to the wrong guy, who are still stressing, and all I can assume is that this is not really an issue of being unsure of paternity but a way of assigning the stress from feeling bad about the regretted event, to something that is easier to worry about.  One way to get over the guilt is to determine that you are not ever going to make that error again, and to pledge to make your partner the world's happiest dad.  That way, something good for him comes out of your action.

[girly18]

Yes I had a period on Feb 5, but I also took plan b after the Jan event & my periods are irregular, so I wasn't sure if it was a true period or not. But I bled heavily for 4-5 days. The guy from Jan is hispanic & I am white, Feb guy is white. Baby doesn't look hispanic at all. I guess I am just worrying over guilt.

[AnnieBrooke]

No, you conceived in February.  Babies just don't come 4 weeks late, and besides, the conception calculator says February 18 conception for your earliest ultrasound-based estimated due date.  I don't know why you are worried about this, didn't you have a period after January 18?

[girly18]

Thank you! I had an US at 7wks, but it was abdominal. It gave EDD 11/18. Other ultrasounds at 11, 14, 20, etc weeks all gave EDD 11/12 plus or minus a day. All ultrasounds were abdominal. I am very thin, so they said they would be able to see more. Baby was born on 11/12 weighing just under 7lbs. 2 encounters are Jan 18 & Feb 10-present. Possible conceived in Jan & US were off & baby was 4 weeks late?

[AnnieBrooke]

While there is a slight difference, especially in the early stages of pregnancy, between the level of detail afforded by abdominal and transvaginal ultrasounds, there is not enough difference to cause a 4-5 week error in assessing the stage of development of the embryo.

[girly18]

Could an abdominal ultrasound at 11 weeks be 4-5 weeks off (Mistake being 11 weeks for actually 15-16 weeks)?