Evaluation of normal and abnormal lips in fetuses: comparison between three- and two-dimensional sonography

The purpose of this study was to determine if three-dimensional (3D) sonography could improve prenatal evaluation of fetal lips in comparison with conventional two-dimensional (2D) sonography.

Sixty-one high-risk pregnant women and 10 low-risk pregnant women were examined with conventional 2D sonography followed by 3D sonography with a volume transducer. The ability to visualize cleft lips and normal lips was compared between the two techniques.

Of the 71 fetuses studied, faces were seen in 68 and not seen in three by either 2D or 3D sonography. Abnormal lips were seen in five fetuses on both 2D and 3D sonograms. Of the remaining fetuses, 3D sonography was able to confirm the presence of a normal lip in 92% (58/63) compared with 76% (48/63) with 2D sonography. In the subgroup of fetuses less than 24 weeks' estimated gestational age, 3D sonography confirmed a normal lip in 93% (38/41) of fetuses as compared with 68% (28/41) for 2D sonography. There was no difference between 3D and 2D in the subgroup of fetuses older than 24 weeks. One false-positive finding of cleft lip was observed at 36 weeks' gestational age with the rendered surface display on 3D sonography, whereas the 3D planar views of the same volume showed the lips to be normal.

3D sonography was able to confirm the presence of normal lips more frequently than did 2D sonography in fetuses less than 24 weeks' gestational age. Abnormal lips were seen on both 2D and 3D sonograms; however, 3D images of cleft lip were easier to understand for both the family and clinical colleagues.