An ultrasound is actually the most accurate way to date a pregnancy because all fetuses grow at a consistent rate during the first trimester and early second. In other words, if your baby measures 9 weeks 2 days when you have your ultrasound, thats how far along you are, no matter when your last period was.
Can ultrasound be wrong about due date?
As pregnancy progresses, the accuracy of an ultrasound for predicting due dates decreases. Between 18 and 28 weeks of gestation, the margin of error increases to plus or minus two weeks. After 28 weeks, the ultrasound may be off by three weeks or more in predicting a due date.
How accurate is a late ultrasound?
The last ultrasound scans underestimated gestational age by a median of 8 days, and by 2 weeks or more in 20 of the 69 cases, as opposed to best dating criteria. Ultrasonic fetal weight estimation was more accurate, but erred by more than 20% in 10% of cases.
Why is my ultrasound due date different?
Your doctor may change your due date based on the ultrasound measurement. This is most likely to occur in the first trimester, especially if the date estimated by the ultrasound differs by more than one week from the date estimated by your doctor based on your LMP.
Can due dates be off by a month?
In fact, only 6% of women deliver on their due date, Cackovic said. I tell patients that really, your due date is a date in the middle of almost a month-long period of time that you could have your baby. The reality is that about 70% of women will have their baby within 10 days of their due date, he said.
How does your stomach feel at 2 weeks?
Bloating. As your body starts to realize youre pregnant, it will probably slow down the digestion process in an effort to deliver more nutrients to baby. This can result in a bit of gas and bloating—hey, maybe it will even look a bit like a 2 weeks pregnant belly! (Not that that exists.)
What is the most accurate way to predict due date?
Ultrasound measurement of the embryo or fetus in the first trimester (up to and including 13 6/7 weeks of gestation) is the most accurate method to establish or confirm gestational age.