Most scans are carried out by sonographers. You may need to have a full bladder for this scan, as this makes the ultrasound image clearer. You can ask your midwife or doctor before the scan if this is the case. The dating scan usually takes about 20 minutes.

What happens at the dating scan?

It involves a blood test and measuring the fluid at the back of the babys neck (nuchal translucency) with an ultrasound scan. This is sometimes called a nuchal translucency scan. The nuchal translucency measurement can be taken during the dating scan.