Conception date accuracy?

how accurate would your estimated date of conception be if you were going by the due date given to you from an ultrasound? for instance my ultrasound said that i was due december 10 and according to that then i concieved around march 19. in other words if i am checking my conception date with the due date given to me by an ultrasound would that be more accurate then trying to figure out your conception date using the 28 day cycle and lmp method?

Conception date accuracy?
Not enough information.





Ultrasound dating is only really accurate if done prior to 12 weeks, and even then it has a leeway of a few days either direction. The later in pregnancy that ultrasound is done, the more inaccurate it becomes (quickly.) By about 20 weeks the est. due date given can be off by 2 weeks either way.





If your menstrual periods are every 28 days, very regular, and you know for sure when the first day of your last period started, then a normal pregnancy due date calculator is fairly accurate on conception, which usually occurs 14 days PRIOR to when you should have started your next period. If your periods are irregular, or you have cycles longer or shorter than 28 days those types of pregnancy due date calculators are not accurate (unless you are able to input the length of your cycle.) If all you want to do is know when you probably conceived figure out when your next period should have started and count back 14 days.





If you want to know your due date and your cycle is more or less than 28 days, you need to add or subtract the number of extra days in your cycle to/from your due date. (IE, if you have 30 day cycles your due date would be the 12th, not the 10th. If you have 25 day cycles, your due date would be the 7th, not the 10th.)





If you have very irregular periods or don't know when the first day of your last menstrual period began then all bets are off! A good midwife or OB could probably have (over time) figured it out but I can't do that here! An early ultrasound would have been your best bet at an accurate due date.





Claudine Crews CPM, LM
Reply:Eh, either way isn't all that accurate. However, using your LMP and a 28 day cycle is a little more accurate on predicting the date of conception, especially if you did not have an ultrasound in the first 10-12 weeks. Nearly all babies grow at the same rate in the first 10-12 weeks, so it is pretty easy and accurate to determine the approximate conception date that way.
Reply:The sooner the ultra sound is


the more aqurate your due date is.


They usally change it once though.


Good Luck Sweety!
Reply:The ultra sound is going to give you a better date of the when you are due. The Naagles rule is a guess. With ultra sound they can tell different stages of growth and development. Go with the ultra sound date.





Todd
Reply:So you must be 4 days over due... well ultrasounds are pretty acurate although nothing is 100% and babies come when they are ready.
Reply:Ok here is what you do to find out your conception date go to google and type in pregnancy calculator. it will bring up a bunch of site the first three is what i would do. any ways on that page it will have these little box's that say enter last day of period you put that in and it gives you how far along you are when your due date is and when you concieved good luck
Reply:The due date is called the estimated due date for a reason. Most women don't give birth on their due date. The end is hard but it's almost over. Good luck and G-d bless.
Reply:Your ultrasound results are the most accurate
Reply:the ultrasounds are pretty accurate.. because they are based on size of the fetus. They were right on with both of my pregnancies, and my sisters as well... within one day actually!
Reply:Always go by the ultrasound. They are more accurate.

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