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A 29-year-old female asked:

Is a six week sonogram accurate to plus or minus four days or plus or minus fourteen days?

3 doctor answers4 doctors weighed in
Dr. Holly Maes
Pediatrics 37 years experience
4 days: Ultrasounds very early like this are quite accurate. The date determined by this early us is usually right on.
Dr. Pavel Conovalciuc
Family Medicine 24 years experience
6 week sonogram: A 6 week ultrasound should be very accurate, so answering your question, 4 days and not 14 days.
Dr. Joseph Accurso
Radiology 30 years experience
Ultrasound +/- 8%: Properly performed and interpreted ultrasound examinations have a variability of 8% plus or minus the measured dating. Ultrasound dating at 6 weeks 0 days should have a 95% confidence range of 5 weeks 4 days to 6 weeks 3 days which is +/- 8%.
Last updated Aug 30, 2015

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