Sleeping on your left side Do you keep finding you wake up on your left side? Read more. The best time to do a 3D or 4D scan is usually towards the end of your second trimester or at start of your third trimester around weeks. Related content:. Can I bring anyone in? Your choice of a free rescan may be appropriate if we are unable to perform the primary purpose of this scan.
If the scan shows there might be a problem, you may be offered another test to find out for certain.
If any problem is found or suspected, the sonographer may ask for another member of staff to look at the scan and give a second opinion. Like an early pregnancy scan, it will also tell you if your pregnancy is ongoing or not. If a problem is found or suspected, the sonographer may ask for a second opinion from another member of staff. If there's a problem, will the scan find it? Can ultrasound harm my baby?