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Dr. Norm S.
Dr. Norm S., Board Certified OB/GYN
Category: OB GYN
Satisfied Customers: 11288
Experience:  Over 30 years of experience in OB/GYN practice, including teaching students. Fellow of American Board of Obstetrics and Gynecology.
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In the uk what is the dating error of an early ultra sound

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In the uk what is the dating error of an early ultra sound scan.
Mine was on the 30th December 2015 and measures 51mm would this mean I conceived around the 23rd October. Lmp was on the 8th October?
Thanks A
What part measured 51mm? Was that the crown-rump length?Do you know the bi-parietal diameter? Thank you.
Customer: replied 1 year ago.
It was crl measured no bi-parietal on my dating scan sheet.
51mm crl corresponds to 11 weeks 4 days gestation. That should be accurate within 7 days either way.That would mean that you got pregnant about October 25 plus minus 7 days (October 18 to November 2).
Customer: replied 1 year ago.
So no way it would be mid September?
Many thanks
No way that it could be anytime in September.You're welcome.Please click the rating stars. Thank you.
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