Heto momsh kung saan ako nagpaultrasou d.  When is the best time to do a 3D/4D Ultrasound? The best time to see your baby's face and features is between 28 and 32 weeks. If you are planning on coming in twice for a 3D/4D ultrasound, we recommend the first visit to take place between 18 and 25 weeks and the second visit between 28 and 32 weeks. We can determine your baby's gender by week 16. Women with twins should visit around 25 weeks, as twins have less space. Generally speaking 3D & 4D imaging is good any time after week 20.