Question 1

are 30+ week ultrasound measurements accurate to date a pregnancy?

Accepted Answer

Yes and no: They are accurate, but only to around +/- 3 weeks.

Question 2

how do 9 week transvaginal ultrasounds date a pregnancy?

Accepted Answer

By measuring the: Size of the fetus and the size equates with weeks gestation.

Question 3

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 4

can longer implantation time affect dating ultrasounds in early pregnancy?can it affect growth estimates in early pregnancy and date you behind?

Accepted Answer

Yes: This usually does not affect the dating more than a few days.  If you keep track of ovulation, that would help your Provider give you a more accurate date.

Question 5

when 1st trimester ultrasounds date pregnancy how do they base the gestational age? do they assume conception occured on cd14?

Accepted Answer

US: First trimester ultrasound is based on biometric measurements only, the embryonic crown-rump length, which is extremely reliable when done by a skilled sonographer. No assumptiosn need be made at all. The ega is however reported correctly, by convention, from the first day of a hypotehtical last menstrual period; so in that regard it 'assumes' conception on cd 14.

Question 6

accuracy at 11wks. pregnant, going by the actual age of pregnancy can it be possible for the ulstrasound to date me 10 days before i even had sex with second partner and 1 day after my first partner?

Accepted Answer

: Evidence suggests that ultrasounds more accurately predict your due date than using your last menstrual period—but only in the first trimester and early second trimester (until roughly 20 weeks). Early ultrasound due dates have a margin of error of roughly 1.2 weeks. After 20 weeks, your Dr will measure your fundal height to see if the baby's growth is keeping on track with the EDD.

Question 7

how find out expected date of pregnanacy by using ultrasound?

Accepted Answer

Standard measures: This is a complicated topic and dependent on how far along you are. Ask the doctor who will be performing your ultrasound.

Question 8

why would an ob change your due date from an ultra sound taken at 9 weeks of pregnancy but not mention until 3 days beore said due date?

Accepted Answer

Common: Bonnie, it is very common to revise the due date based on ultrasound evidence, because it is much more accurate than the first day of your last period. Why they didn't mention it earlier, I can't say, but remember that guessing a due date is an inexact science. Only 5% of babies are actually born on their due date. Hope this helps!

Question 9

my first sonogram of 8 weeks and 2 days of pregnancy says my due date is sept.17, 2013. could i have conceived between dec.15 and dec.26 of 2012?

Accepted Answer

Around xmas: If you estimated due date on 09/17/2013 that  makes  your LMP around 12/11/2012 , usually you get pregnant about 2 weeks after your period so most likely  you conceived around xmas  12/25.

Question 10

is it ok to have ultrasound free pregnancies?i heard ultrasound can harm unborn children.

Accepted Answer

Yes: Certainly, you can request not to have any ultrasounds during your pregnancy. However, ultrasound has been used for decades and there are no known consistent health risks to a developing fetus.  They are safe.  Ultrasound is an easy way to look for potential health issues which may be addressed before delivery, or at least can be anticipated for intervention after delivery.  Trust your ob.

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Doctor answers about:

Ultrasound to date pregnancy

A member asked:

Are 30+ week ultrasound measurements accurate to date a pregnancy?

A member asked:

How do 9 week transvaginal ultrasounds date a pregnancy?

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:

Can longer implantation time affect dating ultrasounds in early pregnancy?can it affect growth estimates in early pregnancy and date you behind?

A member asked:

When 1st trimester ultrasounds date pregnancy how do they base the gestational age? do they assume conception occured on cd14?

A member asked:

Accuracy at 11wks. pregnant, going by the actual age of pregnancy can it be possible for the ulstrasound to date me 10 days before i even had sex with second partner and 1 day after my first partner?

A member asked:

How find out expected date of pregnanacy by using ultrasound?

A member asked:

Why would an ob change your due date from an ultra sound taken at 9 weeks of pregnancy but not mention until 3 days beore said due date?

A member asked:

My first sonogram of 8 weeks and 2 days of pregnancy says my due date is sept.17, 2013. could i have conceived between dec.15 and dec.26 of 2012?

A member asked:

Is it ok to have ultrasound free pregnancies?i heard ultrasound can harm unborn children.

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