Three-dimensional ultrasonography in early pregnancy

Three-dimensional ultrasound was introduced into clinical use over a decade ago. Early attempts on three-dimensional ultrasound were primitive and limited to experimental use only. Recently, it was used as a powerful tool to display three-dimensional fetal appearance and assess normal and pathological conditions. Because of the improvement in image resolution and reconstruction speed, three-dimensional ultrasound is now more and more popular in many centers, and used commonly as an adjunct in prenatal diagnosis. Indeed, a skillful sonographer may usually make the correct diagnosis of fetal anomaly with simply two-dimensional ultrasound. Nonetheless, the situation is gradually changing, because some anomalies have been diagnosed only based on the findings of three-dimensional ultrasound. In spite of that, the application of three-dimensional ultrasound is still less discussed in early pregnancy. In this article, the authors clarify the capability of three-dimensional ultrasound in different anatomic areas, and catalog its clinical merits in the early pregnancy to date. We also present the safety guidelines for its use in the first trimester.