Application of three-dimensional ultrasound in the first trimester

Abstract

The first trimester of pregnancy is the most critical moment for the embryo and fetal development in terms of rapid changes and modification of its internal and external appearance. The modern ultrasound equipment enables us to identify some of these changes as early as 5–7 weeks after the last menstrual period (LMP). The relevance of 3D ultrasound (3D US) in the detection and demonstration of fetal abnormalities has already been proven. Some of the 3D/4D tools have shown some benefits compared to the 2D US when a malformation is present. The 3D images are usually clearer for parents to understand the problem or the normality of the small fetus. There are five main aspects of the 3D/4D US to mention, which are relevant during the first trimester of pregnancy: (1) the multiplanar approach of the embryo and the fetus; (2) the ability to obtain planes that are not accessible with 2D US; (3) the possibility to do an off-line analysis of acquired 3D/4D volumes and telemedicine; (4) the images are usually easier to interpret for parents when displayed with the surface mode; and (5) the increasing amount of tools available to process fetal images and perform different measurements. Answer to the question is it essential to have a 3D/4D ultrasound machine in everyday practice to carry out a first-trimester scan is obviously negative; however, as most of the practitioners do have one nowadays, it is important to point out its benefits and limitations.