Feasibility of Imaging the Uvula at the Midtrimester Anomaly Ultrasound: A Retrospective Study

The fetal palate is not routinely imaged as part of the midtrimester fetal anomaly ultrasound, despite being associated with many syndromes. The "equal sign" depicts the lateral borders of the uvula on 2-dimensional fetal ultrasound. We assessed the feasibility of adding the equal sign to the midtrimester fetal anomaly ultrasound.

A retrospective audit of an ultrasound practice in Cape Town, South Africa was performed. Women with singleton pregnancies presenting for a routine anomaly ultrasound between October 2013 and September 2019 were included.

A total of 5301 ultrasound examinations were performed during the time period. In a sample of 101 cases selected randomly, the equal sign was clearly visualized in 97% (98/101) of cases. It was visualized in sequence while examining the face or brain in 88% (89/101). Mean time to visualize the equal sign was 28 seconds. Total scan time increased by 1.5%. The body mass index had no effect on detection rate. Of the 5301 scans performed during the study period, there were 15 cases where the uvula was abnormal. Ten of these 15 cases had an intact lip. There were no false positive diagnoses of an abnormal uvula.

It is feasible to image the equal sign at the midtrimester ultrasound with a low false positive detection rate.