Prenatal diagnosis: what does four-dimensional ultrasound add?

Introduction: The key benefit of 4D ultrasound lies in providing real-time 3D images of embryonic or fetal movements, previously limited by technological advancement.

Aim: To classify types of first trimester embryonic and fetal movements in normal pregnancies as seen by 4D sonography.

Results: Three types of movements can be visualized in the first trimester: gross body between seven and eight weeks, limb movements after ten weeks and complex limb movements after 11 weeks of gestation.

Discussion: An alteration from the given pattern of motoric development should be considered as an indication for further investigation.

Conclusion: 4D ultrasound enables visualization of more details of the dynamics of small anatomical structures. Therefore, body and limb movements can be visualized a week earlier than with 2D.