Question 1

how is conception date calculated by first trimester ultrasound?

Accepted Answer

Measurements: US uses measurements of the gestational sac and then the growing fetus to date a pregnancy. The appearance of the heart beat. Usually measurements are compared to standards for various parts of the pregnancy and a date assigned.

Question 2

my lmp was feb 8-12. my due date was nov 23.(calculated by my first sonogram).my obgyn informed me my conception date was mar 2. i had intercourse on feb 20th and feb 27-28. what would be sexual intercourse that would had led to my conception date ?

Accepted Answer

: It is not feasible to narrow down as to which episode of sex resulted in conception. What did you doctor mean by conception date? Was it the day egg was fertilized or the day implantation took place? Sperm can live in a women for five days and that adds to the uncertainty of exact date.

Question 3

how accurate is an ultrasound's conception date/due date?

Accepted Answer

The margin: of error for ultrasound pregnancy dating is about 8%.

Question 4

how accurate is an ultrasound at 15 weeks determining possible conception date , due date is nov 19?

Accepted Answer

7-10 days: Usg can predict conception with a accuracy of 7-10 days at this gestation.

Question 5

if ultrasound says i conceived around 10/27, what dates would sex had to have happened for a conception date close to that?

Accepted Answer

Five Days: The standard answer is that sperm live up to five days after emission.  So the closest they can come to is a five day window around conception.

Question 6

if i just had a ultrasound may23 and i was 26weeks and 1day how for along am i today and when is my due date and conception date?

Accepted Answer

You have a Problem: Check your dates... If you really had an ultrasound 5/23 and you were 26 weeks & 1day...Your due date would have been 8/28/12 & you'd be 49 weeks & 4 days pregnant today... 2 months overdue! please clarify your info & take care.

Question 7

if my 8 and 12 week ultrasound gave me a due date of september 28th how accurate is the conception date and how far can it be off ?

Accepted Answer

Depends: The accuracy of the delivery date is variable depending on a number of factors.  Usually the earlier scan is most accurate due to differences in gestational size (weight).  However, the US is a predictor of age of the fetus not the delivery.  The fetus could come early or late even if it is at the due date because labor is not exactly coupled to the fetal age.  However, +/- 2 weeks is a good guess

Question 8

sorry i just had a ultrasound oct23 and i was 26weeks and 1day how for along am i today and when is my due date and conception date?

Accepted Answer

Jan 27: You are approximately 27 wks and 5 days and due date jan 27th.  Please talk to your doctor for more accurate details as she knows your history the best.  We generally prefer not to use a third trimester ultrasound for dating, we prefer to use either last menstrual period and/or earlier ultrasound.  Good luck!

Question 9

i am 8 weeks 5 days according to an ultrasound i have had done. since i have had an ultrasound can i get an accurate conception date?

Accepted Answer

Within about 10 days: The ultrasound dating is calculated from the first day of bleeding from your last menstrual period ± 5 days.

Question 10

what is my conception date with a due date of september 28th giving at my 8 and 12 week ultrasound  ? and how many days can it be off ?

Accepted Answer

1/7/2014: Is the best estimation of the date of conception.  The 8 week ultrasound establishes your due date +/- 5 days.  Therefore it could be few days before or after.   Period dating is the most accurate if you are sure of your last period.

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Doctor answers about:

How to calculate conception date from ultrasound

A member asked:

How is conception date calculated by first trimester ultrasound?

A member asked:

My lmp was feb 8-12. my due date was nov 23.(calculated by my first sonogram).my obgyn informed me my conception date was mar 2. i had intercourse on feb 20th and feb 27-28. what would be sexual intercourse that would had led to my conception date ?

A member asked:

How accurate is an ultrasound's conception date/due date?

A member asked:

How accurate is an ultrasound at 15 weeks determining possible conception date , due date is nov 19?

A member asked:

If ultrasound says i conceived around 10/27, what dates would sex had to have happened for a conception date close to that?

A member asked:

If i just had a ultrasound may23 and i was 26weeks and 1day how for along am i today and when is my due date and conception date?

A member asked:

If my 8 and 12 week ultrasound gave me a due date of september 28th how accurate is the conception date and how far can it be off ?

A member asked:

Sorry i just had a ultrasound oct23 and i was 26weeks and 1day how for along am i today and when is my due date and conception date?

A member asked:

I am 8 weeks 5 days according to an ultrasound i have had done. since i have had an ultrasound can i get an accurate conception date?

A member asked:

What is my conception date with a due date of september 28th giving at my 8 and 12 week ultrasound ? and how many days can it be off ?

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