25/03/2026
As Midwife Sonographers this is a question we are asked very frequently.
Your estimated due date (EDD) is calculated to give an idea of when your baby may arrive, but it’s important to remember that it is an estimate, not an exact date.
Most due dates are initially calculated from the first day of your last menstrual period, assuming a 28 day cycle. However, every woman’s cycle is different, which is why an early pregnancy scan is the most accurate way to date a pregnancy.
During an early scan, we measure your baby from head to bottom (the crown rump length). This measurement allows us to estimate your gestational age and provide a more accurate due date.
An important thing to remember:
Only about 5% of babies are born on their exact due date … each one choosing their own perfect moment 💫
