In 1984，Kazunori Baba at the Institute of Medical Electronics, University of Tokyo, Japan, first reported on a 3D US system, obtaining 3D fetal images by processing the raw 2D images on a mini-computer. At the beginning 3D US suffered from long image processing time and insufficient image quality. Technical advances, particularly in computer technology and the development of new 3D/4D ultrasound probes have led to significant improvements in speed of image reconstruction as well as image resolution. The addition of a time factor permitted“live”or“real time”3D, also called 4D. Conventional two dimensional（2D）US only allows imaging of single planes, requiring the operator to create a 3D image in his/her mind. Three D/4D US offers several image angles and an amazing variety of display modes that do not exist in 2D imaging. Digital storage of volumes enables long-term maintenance without loss of quality, as well as the option of performing“virtual examinations”at any time, by reloading these volumes and navigating through them, even in the absence of the patient. Furthermore, these digital volumes can be sent to colleagues around town or at the other end of Earth, to get their input, after they reloaded them and manipulated them to get their own views. Many physicians were initially skeptical regarding the clinical use of this technique. The First World Congress for 3D Ultrasound in Obstetrics and Gynecology was held in Mainz, Germany, in 1997. The American Institute of Ultrasound in Medicine（AIUM）held a consensus conference in 2005 where 3D US was shown to be able to image a huge number of conditions, both in obstetrics and gynecology（Benacerraf BR, Benson CB, Abuhamad AZ, Copel JA, Abramowicz JS, Devore GR, et al. Three- and 4-dimensional ultrasound in obstetrics and gynecology: proceedings of the American Institute of Ultrasound in Medicine Consensus Conference. J Ultrasound Med. 2005;24:1587-97）. It should be noted that these were circumstances where 3D ultrasound could be useful, not necessarily clinical situations requiring the use of this technology. Is it time, however, to recommend it in routine obstetrical scanning? Undoubtedly, compared to 2D US, 3D/4D US expands the diagnostic possibilities and provides the operator with additional information. In obstetrics the value of 3D/4D US is undisputable in specific clinical situations, such as facial clefts, brain anomalies, cardiac and spinal defects. Improved maternal-fetal bonding has been reported. This technique seems ready for routine use, and has already become part of daily routine in prenatal diagnosis in expert or referral centers. There are no studies comparing 2D and 3D US in centers where practitioners are not 3D experts. Therefore, the question of the value of 3D/4D in routine scanning or as a screening mode remains unanswered.