First-trimester hand measurements in euploid and aneuploid human fetuses using virtual reality.

OBJECTIVE

Although second-trimester and third-trimester reference curves for human fetal hand growth allow for identification of several genetic syndromes, little is known about first-trimester hand growth. We investigated first-trimester hand growth in euploid and aneuploid fetuses.

METHOD: Between 9 and 12 weeks' gestational age (GA), wrist width, hand width, hand length, and hand index were measured in three-dimensional (3D) ultrasound datasets of 112 euploid and 65 aneuploid pregnancies. We constructed reference curves for these measurements in euploid pregnancies and calculated z-scores for measurements in aneuploid pregnancies. Reproducibility was established in a subset of 20 datasets.

RESULTS

While wrist width, hand width, and hand length increased with gestational age, hand index decreased. Intraobserver and interobserver intraclass correlation coefficient values were >0.97. In trisomy 21 cases, wider wrists and hands were observed compared with euploid pregnancies (mean z-scores 1.06, SD 2.04, p < 0.001 and 1.16, SD 1.30, p < 0.001, respectively). Trisomy 18 cases showed narrower and shorter hands (mean z-scores -0.74, SD 1.20, p = 0.009 and -0.97, SD 0.86, p = 0.005, respectively). In trisomy 13 cases, no differences were observed.

CONCLUSION

Reference values are available for first-trimester studies on human hand development. First-trimester hand measurements in trisomies 21 and 18 differ significantly from those in euploid pregnancies and may be useful for early identification of abnormal development.