Early pregnancy dating
Please ask your hospital about this before your appointment.
This is because the scan can provide information that may mean you have to make further important decisions.
For example, you may be offered further tests, such as amniocentesis, that have a risk of miscarriage.
The dating scan can include a nuchal translucency (NT) scan, which is part of the combined screening test for Down's syndrome, if you choose to have this screening.
The second scan offered to all pregnant women is called the anomaly scan, or mid-pregnancy scan, and usually takes place between 18 and 21 weeks of pregnancy.
The scan is carried out in a dimly lit room so the sonographer is able to get good images of your baby. You'll then be asked to lower your skirt or trousers to your hips and raise your top to your chest.