Objective: To construct an institution-specific nomogram of fetal abdominal circumference measurements and determine whether previously published nomograms correctly categorize our population's outer centiles.
Design: Using cross-sectional data from a database of sonographic circumference measurements, a nomogram for abdominal circumference measurements was created by modeling the mean and standard deviation separately. The adequacy of the nomogram was confirmed by assessing the normal distribution of data, verifying goodness-of-fit, and checking residuals. Outer centiles were compared with those from other published nomograms.
Results: The new nomogram for fetal abdominal circumference measurements from 10 070 fetuses provided sufficient data to derive values for the 5th, 10th, 50th, 90th and 95th centiles based on gestational age. Comparisons with other published nomograms indicated that the false-negative rates for classifying our population as < 10th centile or > 90th centile ranged from 11.3% to 90.5% and from 0 to 66.4%, respectively.
Conclusion: Institution-specific nomograms of fetal abdominal circumference measurements are important to avoid incorrect categorization of outer centiles.