A 24-year-old female asked:
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how accurate is an abdominal ultrasound at 7 weeks pregnant? can it be off by 2+ weeks?

2 doctor answers
Dr. Wayne Ingram
Specializes in Obstetrics and Gynecology
Yes: Ultrasound exams have a 'fudge factor' of plus or minus two weeks.
Answered on Jul 24, 2013
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1 comment
Dr. Gerard Honore
28 years experience Fertility Medicine
Abdominal ultrasound in the 1st trimester is not usually the 'best' appropriate test; transvaginal ultrasound will be accurate to within about 1 week if done by a skilled sonographer.
Jul 24, 2013
Dr. Eva Duckett
30 years experience Radiology
Very accurate: Ultrasound is very accurate during early pregnancy for dating. Less than 7 weeks, a transvaginal/endovaginal exam might be performed for better detail.
Answered on Jul 29, 2013

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Related questions:

A 21-year-old male asked:
Dr. Jane Van Dis
17 years experience Obstetrics and Gynecology
Depends: If a woman is thin and the doctor has a good image of the fetus, then abdominal can be just as accurate as vaginal. Margin of error at this gestation ... Read More
A 28-year-old female asked:
Dr. Bruce J. Stringer
46 years experience Radiology
More info: When was your lmp? Have you had any vaginal bleeding? Over what period of time were these ultrasounds done? Have there been any other HCG levels drawn ... Read More
A 35-year-old male asked:
Dr. James Ferguson
45 years experience Pediatrics
No: Ultrasounds are routinely done during pregnancy, often multiple times.Studies have shown no negative effects on the developing fetus.
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A 21-year-old male asked:
Dr. Steven Chmielewski
29 years experience Diagnostic Radiology
Probably not.: First trimester ultrasound is accurate to about a week. This algorithm is based primarily on crown rump length. The date is as accurate as the measure ... Read More

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