Sonographic weight estimation in fetuses with congenital diaphragmatic hernia.

PURPOSE: To determine the accuracy of sonographic weight estimation (WE) for fetuses with congenital diaphragmatic hernia (CDH), and to assess whether certain sonographic models perform better than others in cases of CDH.

MATERIAL AND

METHODS

In a retrospective, multicenter cohort study, the accuracy of WE in fetuses with CDH (n = 172) was evaluated using eight sonographic models and was compared with a control group of fetuses without malformations (n = 172). Each fetus underwent ultrasound examination with complete biometric parameters within 7 days of delivery. The accuracy of the different formulas was compared using means of percentage errors (MPE), medians of absolute percentage errors (MAPE), and proportions of estimates within 10 % of actual birth weight.

RESULTS

Fetuses with CDH had a significantly lower abdominal circumference (AC) in comparison with the control group (293.6 vs. 312.0 mm, p < 0.001). All of the formulas tested in fetuses with CDH, except for the Siemer equation (the only model that does not incorporate any abdominal measurements), showed significantly lower (more negative) MPEs, larger MAPEs, and smaller proportions of estimates within 10 % of actual birth weight in comparison with the control group.

CONCLUSION

The accuracy of sonographic WE in fetuses with CDH is significantly poorer than in fetuses without malformations, principally because of a larger systematic error due to artificially small AC measurements. The development of new, specific models derived from fetuses with CDH could improve the accuracy of WE for infants with this condition.