Dating ultrasound what to expect
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.
You'll be given the chance to discuss it with your maternity team before making your decision. You may like someone to come with you to the scan appointment.
Most hospitals do not allow children to attend scans as childcare is not usually available.
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.
This is because the scan can provide information that may mean you have to make further important decisions.
Most scans show that the baby is developing normally and no problems are found.
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.
This scan checks for structural abnormalities (anomalies) in the baby.
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.