A lot of people wait longer than they need to get a good 3D ultrasound and some come too early. Timing is important to getting the right 3D ultrasound picture. The best time to see fat cheeks in a 3D ultrasound is between 28 and 32 weeks.
The truest answer really depends on what you want to see. Visit 3D ultrasound images week by week and scroll down until the pictures start looking pretty good. This is the best way to know when you are mostly likely to see what you want in a 3D ultrasound.
If you want to see fat cheeks on your baby then 28 to 32 weeks is ideal. You could wait longer, but you don’t have to. If your fluid is good it’s possible to get clear pictures past 40 weeks.
A vertex presentation (also known as cephalic or head down) is ideal to get the very best images. The reason, which no one will tell you, is that it allows the sonographer to position the transducer (ultrasound probe) under the belly fat and have less tissue obstructing the view.
If you want to find out gender, or see the baby’s whole body, the best time is between 14 and 20 weeks. After 20 weeks the baby won’t usually fit within the 70 degree angle offered by most transducers.