Leeds dating scan
If you are overweight or your body tissue is dense, sometimes this can reduce the quality of the image because there is more tissue for the ultrasound waves to get through before they reach the baby.
If it's difficult to get a good image, the scan may take longer or have to be repeated at another time.
Talk to your midwife, GP or obstetrician about any concerns you have.
For many women, ultrasound scans are the highlight of pregnancy.
There are no known risks to the baby or the mother from having an ultrasound scan, but it is important that you consider carefully whether to have the scan or not.
Having a scan in pregnancy is usually a happy event, but be aware that ultrasound scans may detect some serious abnormalities, so try to be prepared for that information.
The sonographer estimates when your baby is due (the estimated date of delivery, or EDD) based on the baby's measurements.
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.
Most scans are carried out by specially trained staff called sonographers.
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.