Three-dimensional ultrasound (3D) is a three-dimensional representation of images obtained by conventional two-dimensional ultrasound. 4D ultrasound is a technique to see the foetus move in three dimensions and in real time. This technique makes it possible to see the foetus moving inside the womb. Images are often high quality and extremely realistic, making it possible to see how the foetus behaves in the womb, like smile, move the face and yawn. Studies show that this technique increases bonding between parents and the unborn child. However, while this ultrasound is basically performed for fun, 4D ultrasound provides relevant information concerning the degree of malformation in certain foetal conditions like a cleft lip. While 4D ultrasound can be performed at any time during pregnancy, weeks 27-32 of pregnancy is the ideal time to observe more defined and developed facial features. The technique has certain limitations and not all images have the same definition; for example, the amount of amniotic fluid, foetal position, the position of the placenta and certain maternal conditions such as obesity diminish optimal images from being taken.