Question 1

how accurate are early ultrasounds?

Accepted Answer

The most accurate: The earlier you get your first ultrasound, the more accurate is the estimate of your due date and the age of the pregnancy. During the first trimester, the dates are within about a week of the actual conception date. Later in the second trimester, you can be at least 2 weeks off. If you were to present for your first sono in the third  trimester there can be 3 or more weeks of uncertainty of dates.

Question 2

how accurate are early ultrasounds? i had my first ultrasound at 6 weeks and all my other ones have been consistent.

Accepted Answer

They may: be more accurate than ultrasounds later on in the pregnancy, but in general the error margin for estimated gestational age is about 8% throughout.

Question 3

how accurate are ultrasounds during early pregnancy? i had one at the er are the ones given in the obgyn office more accurate? thoughts? transvaginal

Accepted Answer

Both are accurate: Er and ob/gyn are both accurate for gestational age; typically transvaginal is more accurate than transabdominal.
Ultrasound performed in the er in early pregnancy are typically ordered to confirm whether or not you are pregnant, and how far along you are. 
The scans typically performed by your ob/gyn are often are more detailed to determine how your fetus and its anatomy are developing.

Question 4

early ultrasounds always accurate? how inaccurate can they be?

Accepted Answer

OB Ultrasounds: The early ultrasounds are the most accurate. They should not be considered inaccurate in any way.

Question 5

how accurate are 6 week ultrasounds and why do some babies come 2 weeks early if ultrasounds are accurate?

Accepted Answer

Fairly accurate: Onset of labor and delivery depends on multiple factors, mostly maternal, and estimates are that 10% of infants are born earlier than 37 weeks.  Age of mother, prenatal care, size and number of babies, uterine shape, maternal smoking or drugs, previous cervical cone biopsy and  maternal infection  are the most common.

Question 6

could very early ultrasound (5 weeks) be not accurate? it showed only 4 weeks, what doesn't match my ovultation. at 12 week it was correct...

Accepted Answer

That's correct: The accuracy is plus or minus a week or so. The prenatal ultrasound dating scan done at 8-11 weeks is more accurate. That means when the doctor says, "The scan dates your pregnancy at 9 weeks," he is actually saying, "The scan dates your pregnancy at 8 to 10 weeks." In almost all normal pregnancies, the exact dates are unimportant.

Question 7

when it is said that early (8 wk) ultrasounds are accurate +/- 2 days, what exactly does that mean?  it is 1 to 2 days accurate of the conception day?

Accepted Answer

They are accurate: EDD are based on 40 weeks from last known normal menstrual period, or 38 weeks from known conception date.U/S dating is based on a database of average fetal anatomic measurements (size of head, abdomen, leg etc) for a particular age.The computer in the ultrasound calculates an EDD based on the average of these measurements. In the first trimester (

Question 8

is lmp more accurate than early ultrasound?

Accepted Answer

No: Early sonograms are more accurate than lmp.

Question 9

how accurate is an ultrasound at 5 weeks 4 days? i was able to see a heartbeat that early. what is the earliest this can be detected?

Accepted Answer

During the 5th: week is about the earliest the heartbeat can be detected.

Question 10

i had a ultrasound at 12weeks my conceive date was may6th and one at 25weeks conceive date may15 which one is more accurate early or later?

Accepted Answer

The first one: The earliest ultrasound study is always used to establish the due date since the earlier the study, the more accurate is the estimate of fetal age. The fact that the fetus is measuring 9 days smaller than average on the second exam may suggest that the fetus is growing a little more slowly than average. Or that the measurements were a little off. At any rate, trust the first estimate for the dates.

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Doctor answers about:

How accurate are early ultrasounds

A member asked:

How accurate are early ultrasounds?

A member asked:

How accurate are early ultrasounds? i had my first ultrasound at 6 weeks and all my other ones have been consistent.

A member asked:

How accurate are ultrasounds during early pregnancy? i had one at the er are the ones given in the obgyn office more accurate? thoughts? transvaginal

A member asked:

Early ultrasounds always accurate? how inaccurate can they be?

A member asked:

How accurate are 6 week ultrasounds and why do some babies come 2 weeks early if ultrasounds are accurate?

A member asked:

Could very early ultrasound (5 weeks) be not accurate? it showed only 4 weeks, what doesn't match my ovultation. at 12 week it was correct...

A member asked:

When it is said that early (8 wk) ultrasounds are accurate +/- 2 days, what exactly does that mean? it is 1 to 2 days accurate of the conception day?

A member asked:

Is lmp more accurate than early ultrasound?

A member asked:

How accurate is an ultrasound at 5 weeks 4 days? i was able to see a heartbeat that early. what is the earliest this can be detected?

A member asked:

I had a ultrasound at 12weeks my conceive date was may6th and one at 25weeks conceive date may15 which one is more accurate early or later?

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