I had a vaginal ultrasound at 6 weeks 4 days prego, how accurate is the due date??

Question

On thursday I will be 30 weeks.. SO far all the scans have been the same...I am measuring bigger, so i wasnt sure if the scan was off or if my belly is just measuring big. Im so clueless when it comes to all of this.Thanks to all who answered before!

Answer 1

Gestational age, determined in a first trimester ultrasound is extremely accurate. We all start life at the same growth rate.

"Today, the crown rump length is a universally recognized term, very useful for measuring early pregnancies. The CRL is highly reproducible and is the single most accurate measure of gestational age."

http://www.obgyn.ufl.edu/obgyn101/Ultrasound/1st_trimester_ultrasound_scannin.htm

"Early in pregnancy (1st trimester), fetuses of the same gestational age all are nearly identical in size. At this time in pregnancy, there is very little difference in size between those fetuses who ultrimately will be large, average size, or small. As pregnancy continues, these genetic and constitutional differences in size become more important clinically. It is not possible, for example to separate a 20 week fetus who is large from a 21 week fetus of normal size, or a 22 week fetus who is small for its age. All three will measure as though they were 21 weeks.....The accuracy of ultrasound in predicting gestational age gets worse as the pregnancy advances. By 20 weeks, ultrasound is accurate only to within plus or minus two weeks, and by the third trimester, its accuracy falls to plus or minus 3 weeks."

http://www.obgyn.ufl.edu/obgyn101/Ultrasound/2nd%20and%203rd%20Trimester%20Ultrasound%20Scanning.htm

Answer 2

The due date estimated from the ultrasound is probably within two weeks of your actual due date, and there is a chance that it will continue to be your due date. Your 20-week ultrasound will give a more accurate due date. The first several weeks are hard to tell because there isn't much to look at, it is calculated usually then by size, shape, and presence or lack of heartbeat (usually appears right around week 5). My due date went from June 21 to June 14 to June 5. I ended up having my daughter on May 25th but I was induced.

Good luck, and congrats :-)

Answer 3

i had a vaginal u/s done with my first.
i was 8 weeks late for my period at the time
dating scan said i was 6wk5day's

moved up to london to live with my partner's mum for a while and because they didnt have my notes they sent me for another dating scan

According to the first scan i would have been about 10wks at the time

yet this dating scan put me at 12-13wks and gave me a due date of 28th may where as 1st dating scan said i think 10th june

I had my son may 24th so 4 days early to the 2nd dating scan yet 2-3 wks early for the 1st dating scan

when my son was born my midwife said he looked like he was on time so im guessing that my 2nd dating scan was far more accurate

Answer 4

this early on, it is pretty accurate as far as finding out the age of the fetus and for charting growth, but as far as the due date goes, it is always an estimate.

Only one woman I know has given birth on her due date. It is called an Estimated Due Date (EDD) because you can come early or late, you can be induced or have to schedule c-section, or you can have emergency labor or c-section, all very different dates than your EDD. The EDD is just to give you a time limit to prepare and to let you know the ideal date for the maximum gestational development before giving birth.

It is always an estimate!

Answer 5

Mine was pretty accurate ( my 10 week ultra sound age matched up perfectly with my 20 week ultra sound) but the age can vary because the ultra sound estimate gestation age by size of the baby and if you have a smaller or larger baby than average, it would cause your gestation age to be a little off. My two ultra sounds and blood testing have all been within a few days of eachother.

Answer 6

Really accurate! The earlier in your pregnancy the better the chance of being on. Later ultrasounds aren't as accurate due to different rates of development.

Answer 7

My due date is November 14th and in accordance to the early test my theory date develop into the twenty 2d February.. So yours could be around Feb twenty third, supply or take some days as they are actually not particular to be a hundred% precise.

Answer 8

Very accurate. Babies grow at the same rate until 8 weeks or so. So set that day aside, because baby's coming home!

TX Mom

Answer 9

It should be very close due to the size and development of them are all about the same at such a early stage. Congrats good luck

Answer 10

It should be very accurate if they did the vaginal ultrasound. Mine was accurate and my baby was born on the day i was due.