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how to calculate conception date from ultrasound

A 30-year-old female asked:
Dr. Paul Slawek
53 years experience Radiology
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 ... Read More

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A 31-year-old female asked:
Dr. Shari Jackson
20 years experience Radiology
Calculator: Using a reverse due date calculator, you can enter the estimated due date and the calculator will determine the likely date of conception based on ave ... Read More
A 49-year-old member asked:
Dr. Deborah Smith
34 years experience Fertility Medicine
Internet: Go to this website it will help you figure it out http://www.Babymed.Com/conception-calculator.
A 47-year-old member asked:
Dr. Michael Gabor
32 years experience Diagnostic Radiology
The margin: of error for ultrasound pregnancy dating is about 8%.
A 50-year-old member asked:
Dr. Edward Jacobs
45 years experience Obstetrics and Gynecology
Naegle's rule: By universal convention, a pregnancy is dated in weeks since the date of the last menstrual period. The due date is 40 weeks from the first day of th ... Read More
A 39-year-old female asked:
Dr. Michael Sparacino
36 years experience Family Medicine
See below: Subtract 3 months from your first day of your last menstrual period, then add 1 week.
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A 49-year-old member asked:
Dr. Alan Patterson
41 years experience Obstetrics and Gynecology
Your OB can: Show you on an OB wheel you are due 38 weeks from your conception date if you were having 28 day cycles.
A 40-year-old member asked:
Dr. Alan Patterson
41 years experience Obstetrics and Gynecology
U are due: 38 weeks from the conception date, your OB can show you on your ob's pregnancy wheel, and I am sure your OB will get an ultrasound for dating and viab ... Read More
A 44-year-old member asked:
Dr. Alan Patterson
41 years experience Obstetrics and Gynecology
38 weeks earlier: If your periods were every 28 days, your OB can help you figure it out that is part of your ob's job.
A 54-year-old member asked:
Dr. Alan Patterson
41 years experience Obstetrics and Gynecology
See your OB: Not a good situation, your OB can do an ultrasound for dating purposes and blood tests can be done on the baby after delivery and the 2 guys to determ ... Read More
A 55-year-old member asked:
Dr. Barak Rosenn
38 years experience Maternal-Fetal Medicine
Use an app: There are many apps available where you can enter your due date and get the date of conception (look for "pregnancy wheel". Alternatively, if you know ... Read More
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A 28-year-old female asked:
Dr. Antonio Gargiulo
31 years experience Obstetrics and Gynecology
Naegele's Rule: The naegele's rule estimates the expected date of delivery (edd) by adding one year, subtracting three months, and adding seven days to the first day ... Read More
A 53-year-old member asked:
Dr. Grant Linnell
23 years experience Radiology
Equation: Typically, the crown rump length is used to calculate gestation age and edc or estimated date of confinement(the delivery date). This can be used, how ... Read More
A 50-year-old member asked:
Dr. J. David Prologo
19 years experience Interventional Radiology
Yes: Yes. Well, as close as possible. The "estimated gestational age" will give you a range based on the size of the fetus, usually +/- less than a week.
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A 36-year-old female asked:
Dr. Alvin Lin
Dr. Alvin Lin answered
29 years experience Geriatrics
Yes. Very.: Early ultrasounds are very accurate at predicting delivery date. However, we tend to stick w/that calculated from last menstrual cycle if info is avai ... Read More
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A 50-year-old member asked:
Dr. Gregory Gapp
39 years experience Obstetrics and Gynecology
Add 38 weeks : The due date is normally 40 weeks from the first day of the last menstrual period based upon an assumption that ovulation occurs on day 14. If one kn ... Read More
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A 31-year-old female asked:
Dr. Steven Weissberg
54 years experience Obstetrics and Gynecology
Good: Fairly accurate if your periods are regular and you keep track of your dates.
A 46-year-old member asked:
Dr. Alan Patterson
41 years experience Obstetrics and Gynecology
Go on the internet: U can find everything , just use google search engine and your OB can show u on a pregnancy wheel and probbaly give u an extra one, we get them for fr ... Read More
A 52-year-old member asked:
Dr. James Ferguson
45 years experience Pediatrics
Depends on variables: Early projections are based on a woman's history which can be inaccurate.Later data derived from an ultrasound and or other measures tend to be more c ... Read More
A 56-year-old member asked:
Dr. James Ferguson
45 years experience Pediatrics
Depends on variables: Early projections are based on a woman's history which can be inaccurate.Later data derived from an ultrasound and or other measures tend to be more c ... Read More
A 38-year-old male asked:
Dr. Craig Keathley
23 years experience Obstetrics and Gynecology
Pregnancy dating: I assume you are talking about ultrasound measurements. The accuracy depends on when the ultrasound is performed-- an early ultrasound (8-10 weeks) i ... Read More
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A 32-year-old female asked:
Dr. Jay Bradley
17 years experience LASIK Surgery
Baby size: Dates are based on size measurements of baby and back calculated.

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