Real-time 3-D sonographic observation of fetal facial expression

Aim: There have been a few reports about 3-D sonographic observation of fetal movements using dynamic 3-D sonography. However, dynamic 3-D sonography is not real-time, the frame rate being in the region of 4-6 frames per second depending on the size of the region of interest and the number of lines employed. Recently, a new faster 3-D sonography, which acquires up to 28 frames per second, has become available. Using this system, we studied a full range of fetal facial expressions during pregnancy. Methods: A total of 17 normal fetuses in 16 pregnancies (15 singletons and one twin) at 20-38 weeks' gestation was studied using a transabdominal real-time 3-D ultrasound machine. This 3-D ultrasound machine proved capable of providing continuous 3-D sonographic images every 0.05 and 0.035 s. The fetal face was monitored for 15 min for each subject. Results: Fetal eyelid movement (fetal blinking) was observed in three of 17 fetuses (17.6%). Double blinking was identified in one fetus at 38 weeks. Various types of mouth movement (yawning, a little opening, chewing, and subtle lip movement) could be observed in nine of 17 fetuses (52.9%). In the course of yawn-like opening of the mouth, tongue movements such as tongue thrust and tongue click were clearly shown in three fetuses (17.6%). A lingula movement was also identified in the course of tongue movement. Conclusion: Real-time 3-D sonography provides a novel means for evaluation of fetal movement, particularly fetal facial expression, in the second and third trimesters. Real-time 3-D sonography might be an important modality in future fetal behavior research and in evaluation of fetal well-being.