Reference values for the right and left fetal choroid plexus at 11 to 13 weeks: an early sign of "developmental" laterality?

The purpose of this study was to establish reference values for the length, area, and circumference of the right and left fetal choroid plexus at 11 to 13 weeks with respect to the fetal biparietal diameter and to compare the right to the left side. We conducted a prospective study on 114 fetuses at 11 to 13 weeks undergoing first-trimester screening for aneuploidy and structural fetal abnormalities. After the establishment of the fetal situs, the plane of the "butterfly" was obtained on all fetuses, from which the length, area, and circumference of both the right and left choroid plexus were obtained and the right and left sides compared. Using a paired t test, analysis of variance, scatterplots, and linear and logarithmic fittings, reference ranges and charts for the length, area, and circumference of the choroid plexus were then formulated according to their relationship to the fetal biparietal diameter. P < .05 was considered statistically significant. Reference values for the length, area, and circumference of the fetal choroid plexus, with respect to the fetal biparietal diameter, were established. There was a statistically significant difference between the right and left sides for all parameters, with all measurements statistically greater on the left side (P < .0001). Reference values for the length, area, and circumference of the fetal choroid plexus at 11 to 13 weeks are presented. These may prove to be of clinical importance in the early screening for central nervous system abnormalities. In addition, the statistically significant difference between the right and left sides may be an early sign of "developmental" laterality.