What Does My First Trimester Ultrasound Scan Test Report Indicate?

Posted on Sat, 27 Jun 2015

Medically reviewed by Ask A Doctor - 24x7 Medical Review Team

Sat, 27 Jun 2015 Answered on

Tue, 14 Jul 2015 Last reviewed on

Question : Is it possible for first trimester ultrasounds to be off by 7-10 days. When my wife first went for her ultrasound she was 6 weeks 4 days conception date January 25th. I knew that wasn't right being she got a 4 positive pregnancy test on February 25. 6 weeks later we went back instead of the clinc we had an actually doctor measure her and 14 weeks date of conception january 16. He said that baby was without doubt conceived between January 15-20. But her period started on the 10th of January. I was just wonder if someone could help me out in seeing which date is right? Cause I was told the earlier ultrasounds were more accurate with the XXXXXXX if a 7 day error.

I'm sorry she got 4 positive pregnancy test on February 2nd.

Answered by Dr. Dr. Rakhi Tayal (1 hour later)

Brief Answer:
Near 20th January.

Detailed Answer:
Hello,
Thanks for trusting us with your health concern.
The earlier ultrasound should be more accurate in calculation of date. But if her pregnancy test came positive on 2nd Feb, it means she conceived at least 12 days prior to the positive test. It means that her date of conception is around 20th January. The minor variation of 5-7 days is possible in calculating the date of conception as it depends on the accuracy with which the measurements are taken during ultrasound scan.
Please feel free to discuss further. I will be glad to answer the follow up queries that you have.
Wishing you good health.
Regards.
Dr. Rakhi Tayal.
For future query, you can directly approach me through my profile URL http://bit.ly/Dr-Rakhi-Tayal

Above answer was peer-reviewed by : Dr. Chakravarthy Mazumdar

Follow up: Dr. Dr. Rakhi Tayal (1 hour later)

Okay doctor swears first date was wrong. The first one was done at clinc. Maybe there ultrasound wernt as good as doctor so a little less accurate. He swears January 15-20. But January 24th matches perfect with lmp. But it is not possible for a 25miu urine test to pick pregnancy up that early correct?

Answered by Dr. Dr. Rakhi Tayal (19 minutes later)

Brief Answer:
Yes. You are correct.

Detailed Answer:
Hello.
Thanks for writing again.
Yes. An ultrasound done at the clinic may not be that accurate. Also, a 25mIU test cannot be positive until after 12 days post conception. So, a date before 20th January is more accurate.
Hope my answer is helpful.
Do accept my answer in case there are no further queries.
Regards.

Above answer was peer-reviewed by : Dr. Chakravarthy Mazumdar

Follow up: Dr. Dr. Rakhi Tayal (15 minutes later)

Thank you so much for help rating you 5 stars

Answered by Dr. Dr. Rakhi Tayal (2 hours later)

Brief Answer:
You are welcome.

Detailed Answer:
Hello.
Thank you.
I am happy I could help.
Please do recommend our services to others too in case you found them helpful. For future query, you can directly approach me through my profile URL http://bit.ly/Dr-Rakhi-Tayal
Wishing you the best in whatever you do.
Best regards.

Above answer was peer-reviewed by : Dr. Chakravarthy Mazumdar