When ultrasound was used instead of certain LMP, the number of postterm pregnancies decreased from 10.3% to 2.7% (P <. 001). Conclusion: Ultrasound was more accurate than LMP in dating, and when it was used the number of postterm pregnancies decreased.When ultrasound was used instead of certain LMP, the number of postterm

What scan is most accurate for due date?

The earlier the ultrasound is done, the more accurate it is at estimating the babys 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.

Can first dating scan be wrong?

It is very common when scanning an early pregnancy to find that the due date does not match the menstrual history. Sometimes the dates can be more than a week off and sometimes even as much as 4 weeks.