A dating scan might be recommended before 12 weeks to confirm your due date if you are unsure of your last menstrual period or your date of conception. The scan is optional and not everyone will have it. You can discuss whether you want or need a dating scan with your doctor or midwife.
Are dating ultrasounds necessary?
Many women are uncertain of exactly when conception happened. Ultrasound can tell you how many weeks pregnant you are, based on the size of your fetus. Dating ultrasounds are most accurate when they happen between 7-12 weeks, and are calculated by measuring the fetus crown-rump length.
How important is a dating scan?
A dating scan is an ultrasound examination which is performed in order to establish the gestational age of the pregnancy. Dating scans also reveal other important information such as: the number of fetuses and gestation sacs. the presence of a heart beat.