Okay, so the thing is, 3D/4D ultrasounds are generally considered safe when done by qualified technicians, but since this is about your baby's health and safety, I'd really recommend asking your OB about it first, they know your specific pregnancy and can give you the best advice on timing and frequency. A few of us mums have done it for keepsakes and it was fine, pero honestly it's better peace of mind kung approved ng doctor mo muna, kasi iba-iba ang pregnancy situations natin. Just ask your OB, and if they're good with it, go ahead and enjoy those cute 3D baby photos!