the baby and its heart beat can be detected relatively easily with trans-abdominal and trans-vaginal examination.

baby dating scans accurate-75

The size of the baby correlates less and less with its age as time goes on.

Ultrasound examinations from 12 to 22 weeks are regarded as being within 10 days of accuracy (or up to 10 days earlier or 10 days later than the woman's calculated due date).

Ultrasounds performed during the first 12 weeks of pregnancy are generally within 3 - 5 days of accuracy.

The most accurate time is between 8 and 11 weeks gestation.

wife is 9 weeks pregnant with twins, she has on and off bleeding.

can you describe the difference between the scan at this later stage in a pregnancy?Sometimes a trans-vaginal examination shows that your pregnancy is less advanced than expected.The earlier the ultrasound is done, the more accurate it is at estimating the baby's due date.had my first scan yesterday at what i thought was 11 4, calculated from my last period.be very accurate (somewhere between 95 and a hundred percent), particularly after.) and now at both of my 8 week and 12 week scans, they have told me i'm almost 2 weeks ahead..Ultrasounds performed after 22 weeks gestation cannot be used to estimate the due date of the baby because the size no longer reflects the age very well.