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A member asked:
What week in pregnancy is most accurate in ultrasound dating?
5 doctors weighed in across 2 answers
6-8 weeks: Ultrasound dating is most accurate early in the pregnancy using the crown-rump length (crl) of the small fetus. The measurement can be done starting around 6 weeks. While crl can be used for dating until 12 weeks, it is most accurate during 6-8 weeks when the accepted error is only about 3 days from actual date.
Answered 7/17/2013
5k views
7-13 weeks: The most accurate measurement for dating is the crown-rump length at between 7 and 13 weeks gestation. Ultrasound error is +/- 8%. At 12 weeks that is +/- 1 week, and only +/-4 days at 7 weeks.
Answered 12/9/2013
5k views
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