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What is the range of accuracy for an 11 week abdominal ultrasound? Possible to mistake an 14-15 weeks fetus for an 11 week fetus? Crl measured 45mm.

5 doctors weighed in
Dr. William Brown
Gynecology
4 doctors agree

In brief: Sono reliable

For dating pregnancy, an ultrasound at the stage you define is a very good time to do so.
A fetus that demonstrates cardiac activity and appears to be 11 wks by crl is reliably 11 weeks. That's one reason for doing ultrasound. Abdominal ultrasound of the fetus at this stage does have limited accuracy with regard to fetal anatomy, but dating should be quite reliable.

In brief: Sono reliable

For dating pregnancy, an ultrasound at the stage you define is a very good time to do so.
A fetus that demonstrates cardiac activity and appears to be 11 wks by crl is reliably 11 weeks. That's one reason for doing ultrasound. Abdominal ultrasound of the fetus at this stage does have limited accuracy with regard to fetal anatomy, but dating should be quite reliable.
Dr. William Brown
Dr. William Brown
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