12 week dating scan expect agile backdating
The nurse or assisting staff will usually cover your legs with a sheet while the scan is happening.
If you're having an abdominal scan, you will need to have a full bladder, so it's best to drink lots of water before you arrive.
It's wonderful to see the little blob with a heartbeat that will become your baby.
Usually two scans are done during the first trimester.
However, the accuracy of the ultrasound examination is always dependent on the skill of the sonographer and the quality of the equipment.
The earlier the ultrasound is done, the more accurate it is at estimating the baby's due date.
These scans are only used to estimate the due date of your baby if this is all you have to go on.
If you have more than one ultrasound during your pregnancy, giving you 'multiple dates', then the earliest ultrasound estimate should be used, because it will be more accurate.
This is because the fetus is growing so quickly that there is a big difference in size from week to week.
Also the fetus cannot bend and twist too much yet, so the length of the body is fairly constant.