Although sometimes known as the reassurance and viability scan, your 12 week scan is more typically referred to as the dating scan. Bear in mind that you may not have your scan at exactly 12 weeks; it usually takes place between your 10th and 14th week of pregnancy1.
During the first scan your sonographer will check the size of your baby to give a more accurate idea how many weeks you’ve been pregnant and your due date. It will provide clarity on whether you are expecting more than one baby and the scan will also determine the ‘viability’ of the pregnancy by confirming that the baby is growing as expected within the womb and developing correctly. The scan is harmless to mother and baby and will typically take 20 to 30 minutes for the sonographer to complete before he or she provides a report for your midwife to share with you.