Variation in fetal ultrasound biometry based on differences in fetal ethnicity

Objective

The objective of the study was to evaluate whether fetal ultrasound biometry is affected by variation in fetal ethnicity compared with white controls.

Study Design

This was a retrospective observational study of ultrasound biometry in pregnant women with accurate gestational age.

Results

Three hundred five white, 370 Asian, 895 part Hawaiian, 76 Pacific Islander, and 311 white Asian fetuses were analyzed. At 18 weeks gestation femur length was significantly shorter in Asian and white Asian. Humerus length was significantly shorter in Asian, part Hawaiian, and white Asian. White genetic sonogram was positive 14% for femur and 15% for humerus. The following was found: Asian 29% femur (odds ratio [OR], 2.58; 95% confidence interval [CI], 1.70-3.92), 25% humerus (OR, 1.86; 95% CI, 1.23-2.82); part Hawaiian 21% femur (OR, 1.67; 95% CI, 1.14-2.45), 23% humerus (OR, 1.64; 95% CI, 1.13-2.38); Pacific Islander 27% femur (OR, 2.37; 95% CI, 1.23-4.54), 33% humerus (OR, 2.76; 95% CI, 1.47-5.14); and white Asian 20% femur (OR, 1.56; 95% CI, 1.01-2.46), 22% humerus (OR, 1.56; 95% CI, 1.01-2.42).

Conclusion

Genetic sonogram was screen positive more frequently because of shorter long bone measurements in all nonwhite ethnicities.

Key words: Down syndrome, ethnicity, femur length, genetic screening, humerus length