2 doctors weighed in:

Can a vaginal ultrasound be off 5 weeks?

2 doctors weighed in
Dr. Dennis Higginbotham
Obstetrics & Gynecology
1 doctor agrees

In brief: Probably not

Any type of ultrasound at any point in pregnancy has a range of error much less than 5 weeks.
At worst a scan in the late third trimester is the least accurate but still within a range of error of 23 days or less. Trans-vaginal pregnancy dating is usually done before 14 weeks and is within 4 to 14 days depending on how far along the pregnancy is.

In brief: Probably not

Any type of ultrasound at any point in pregnancy has a range of error much less than 5 weeks.
At worst a scan in the late third trimester is the least accurate but still within a range of error of 23 days or less. Trans-vaginal pregnancy dating is usually done before 14 weeks and is within 4 to 14 days depending on how far along the pregnancy is.
Dr. Dennis Higginbotham
Dr. Dennis Higginbotham
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