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Doctor insights on: What Is The Margin Of Error For Due Dates Based On Early Ultrasound

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Is the margin of error in a 1st trim ultrasound based on error of measurements or assigning a due date? I hear diff things about how "off" they can be

Is the margin of error in a 1st trim ultrasound based on error of measurements or assigning a due date? I hear diff things about how "off" they can be

Gestational age: It is reported as number of days that gestational age could be off, in days. Assuming that babies all mature similarly (a fairly good assumption within a week or two) this also applies to expected delivery date. You have asked at least 3 questions about this topic. I suggest you read something more definitive such as this http://www. Nlm. Nih. Gov/medlineplus/pregnancy.Html. Read more

Dr. Michael Gabor
2,263 Doctors shared insights

Sonogram (Definition)

An ultraound, also known as a sonogram, is a painless and relatively inexpensive imaging test that utilizes sound waves instead of ionizing radiation. There are no side effects. Ultrasound can give us two-dimensional, and in some applications three-dimensional, images of structures and organs in virtually any part of the body. In addition to diagnostic uses, such as evaluating abnormalities in the abdomen, pelvis, and breast, ultrasounds are commonly used to guide needle and catheter placement in a variety of surgical ...Read more


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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?

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?

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. Read more

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What changes a due date by 4 days? Original due date was based on LMP only and then changed to 4 days earlier after 12wk ultrasound. U/s this precise?

What changes a due date by 4 days? Original due date was based on LMP only and then changed to 4 days earlier after 12wk ultrasound. U/s this precise?

Same date: A four day difference is mathematically speaking no difference. You are within the margin of error of a sono machine. A due date simply marks the gestational age if 40 weeks. In this case either date is appropriate. You and your doctor can choose which to go by. Ask your doctor why he or she chose one over the other. Read more

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What is the most time an early ultrasound can be off on a due date? I.E. 2 wks, 3 wks?

What is the most time an early ultrasound can be off on a due date? I.E. 2 wks, 3 wks?

7-13 weeks: The most accurate measurement for dating is the crown-rump length at between 7 and 13 weeks gestation. Read more

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Hi do they date due date by crl in early ultrasound is that how they get the due date?

LMP: The most accurate way of assessing a person's due date is by providing an accurate date of the last menstrual period. When that is not available then a number of factors can contribute to estimating due date. This includes measurements of the uterus and measurements of the fetus at various locations. Read more

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I know it's not a big difference, but what would change a due date from june 3 to may 31? (based on 12 week ultrasound).

Different size is OK: An ultrasound measurement and fetal age calculations are based on averaging many pregnant women and following them until birth of the baby. There are many factors that could alter the growth of the fetus, and babies come in all sizes, so the dates during early pregnancy are reported as a certain date plus or minus 5 days, 10 days, etc. The earlier the ultrasound, the more accurate the dating. Read more

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Early ultrasound put me at 6 weeks 6 days. Due date april 26. How possible is conception from july 23-26?

Early ultrasound put me at 6 weeks 6 days. Due date april 26. How possible is conception from july 23-26?

More likely 8/3: That seems a little outside the range of possibility, if your ultrasound is believed to be accurate. In first trimester, ultrasounds are off by as much as +/- 5 days. Thus 5 days back from 8/3 is around 7/29. 7/23-7/26 seems unlikely, then. Hope that helps! Read more

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My due date based on a 7w1d ultrasound is Sep. 2nd but my LMP is Aug. 13th. Which due date is more accurate.

My due date based on a 7w1d ultrasound is Sep. 2nd but my LMP is Aug. 13th. Which due date is more accurate.

Ultrasound: Generally speaking, a first trimester ultrasound is more accurate. If the two dates are within a couple of weeks, generally you keep the LMP dates. However, farther apart than that, you shift to the ultrasound dating because of its increased accuracy.. Read more

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If my due date measures august 29th with conception december 6, and my baby decides to come early does that mean ultrasound measured wrong or no?

If my due date measures august 29th with conception december 6, and my baby decides to come early does that mean ultrasound measured wrong or no?

No: The due date is just a estimated date of when the full pregnancy will be complete. There are many factors that can lead to an early birth and often a baby can be late for no reason. The due date is only the date that completes 9 months. That's all. Read more

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So everyone says early ultrasounds are more accurate then LMP so mine has 4 day difference between edd so should I not go by ultrasound due date?

Within 4 days is: No real difference. There is nothing magical about either date, except for 2 things: 1. If the lmp is different from the early OB us dating by more than 2 weeks, the lmp is probably wrong. 2. What everyone wants to happen is appropriate interval growth - meaning the fetus grows in size to match the time since the last us - that means growth is happening normally. Read more

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Why do they change your due date nin the second trimester if early ultrasounds are accurate?

Why do they change your due date nin the second trimester if early ultrasounds are accurate?

Being Pregnant: In reality this is not common or normal. Thus most of us here would defer to your OB to explain this. You are correct. The early ultrasounds are usually the most accurate for dating. There must be a reason and I would direct you to your OB to confirm why this was done in your situation. Read more

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Why my Dr change due date from 07/13 to 07/27 after ultrasound 1st date was based off period. Which date is more accurate went from 10wks to 8wks?

Why my Dr change due date from 07/13 to 07/27 after ultrasound 1st date was based off period. Which date is more accurate went from 10wks to 8wks?

Ultrasound: The earlier the ultrasound is done, the more accurate it is. Ultrasounds are more accurate than dating by menstrual periods. An ultrasound done at 8 weeks, such as yours, has an error of 0-1 days. Your due date given by your 8 week ultrasound it your actual due date. Read more

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My due date may 14 from ultrasound and if I go two weeks early does that change who the father of my baby is? Guy a was aug 3 then aug 8, 12, 15, 21 is b

My due date may 14 from ultrasound and if I go two weeks early does that change who the father of my baby is? Guy a was aug 3 then aug 8, 12, 15, 21 is b

Hmmm.: Sounds like you just don't know who the father of your baby is. There isn't any way go know with 2 partners in the same time frame. The only way to deal with this is to be honest with everyone. Have your baby and get dna testing. It will be the best thing for you, your baby and the father. And the other guy. Good luck! Read more

Dr. Chevies Newman
1,113 Doctors shared insights

Premature (Definition)

Very premature is a condition in which a baby is delivered between 28 and 31 weeks' gestation. Depending on how premature, how sick, and how lucky or unlucky a baby is, he can get brain problems, cerebral palsy, blindness, deafness, developmental problems, learning disabilities, severe lung diseases, infection and loss of some intestines, etc... Babies who are only moderately premature usually ...Read more