Question 1

are ultrasounds accurate at dating conception at 12 weeks?

Accepted Answer

Not as accurrate: As they are at 4-6 weeks.

Question 2

are 11week ultrasounds accurate for dating? margin of error?

Accepted Answer

Varies: The range of error for an ultrasound at that point would likely be around +/- 8 days.

Question 3

are transvaginal ultrasounds more accurate in dating than abdominal ultrasounds?

Accepted Answer

Depends: On the size if the baby. Transabominally is fine as the baby increases in size. If it is really small then tv is bettet.

Question 4

are 11 week ultrasound more accurate for dating conception than 6 week ultrasound, both are transvaginal?

Accepted Answer

Not necessarily: Due dating pregnancies is more accurate with more than one ultrasound performed. However, the 6 week ultrasound might be more accurate in dating your conception. Either way ultrasounds have a 'fudge factor' of 1 to 2 weeks in determining accuracy.

Question 5

why is it better to wait until 8 week gestation versus seven weeks gestation in order to have an accurate dating ultrasound?

Accepted Answer

Untrue: this is inaccurate: ultrasounds are certainly quite sensitive at both 7-8 weeks. Consult your oB- there is no logic in this statement.

Question 6

is a dating ultrasound accurate showing 8 weeks if the fetus has iugr and woman has no known lmp? can the fetus actually be 20 weeks along and just look like 8 weeks due to iugr

Accepted Answer

Quite accurate dates: 20 weeks never looks like 8 weeks, just like a 20 year-old who was malnourished and neglected all his life will still not look anything like a normal 8 year-old boy. In a natural pregnancy, ultrasound dating that shows an 8 week fetus is an estimate that the pregnancy is 7-9 weeks. Avoid overthinking this, unless it is 100% impossible that there was a sperm meeting an egg 5-7 weeks ago.

Question 7

are abdominal ultrasounds as accurate for dating as vaginal around 11 weeks of pregnancy? what is the margin of error for abdominal at this gestation?

Accepted Answer

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 is still +/- 5 days. After 14 weeks that number increases to +/- 10 days.

Question 8

how accurate are ultrasounds for dating pregnancy what's the margin of error. if my due date is oct 31, what are the dates i could have gotten pregnant?

Accepted Answer

What year?: It would seem that you would have to conceive on feb.. 8, 2014 to give birth on 10/31. If the question is of historical interest, i would need to know when the ultrasound was done. Otherwise, you might want to check the dates you provided.

Question 9

is a 9 week or 20 week ultrasound more accurate for dating a pregnancy?

Accepted Answer

9wk: Early in the pregnancy the baby grows at a certain known rate.   The 9wk sonogram is by far more accurate for dating.

Question 10

my first ultrasound showed only a 9mm gest sac. 2 weeks later they could see the baby, measuring 7w1d. how accurate are these measurements for dating?

Accepted Answer

Pretty standard.: Although there is usually some plus/minus variance in the measurement, these measurements have been established and standardized so they are pretty accurate.

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Doctor answers about:

Ultrasound accurate dating

A member asked:

Are ultrasounds accurate at dating conception at 12 weeks?

A member asked:

Are 11week ultrasounds accurate for dating? margin of error?

A member asked:

Are transvaginal ultrasounds more accurate in dating than abdominal ultrasounds?

A member asked:

Are 11 week ultrasound more accurate for dating conception than 6 week ultrasound, both are transvaginal?

A member asked:

Why is it better to wait until 8 week gestation versus seven weeks gestation in order to have an accurate dating ultrasound?

A member asked:

Is a dating ultrasound accurate showing 8 weeks if the fetus has iugr and woman has no known lmp? can the fetus actually be 20 weeks along and just look like 8 weeks due to iugr

A member asked:

Are abdominal ultrasounds as accurate for dating as vaginal around 11 weeks of pregnancy? what is the margin of error for abdominal at this gestation?

A member asked:

How accurate are ultrasounds for dating pregnancy what's the margin of error. if my due date is oct 31, what are the dates i could have gotten pregnant?

A member asked:

Is a 9 week or 20 week ultrasound more accurate for dating a pregnancy?

A member asked:

My first ultrasound showed only a 9mm gest sac. 2 weeks later they could see the baby, measuring 7w1d. how accurate are these measurements for dating?

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