Ultrasonographic measurement of the abdominal circumference in fetuses with congenital diaphragmatic hernia

Objective: To determine whether ultrasonographic measurements of the abdominal circumference are smaller in fetuses with congenital diaphragmatic hernia and whether this is reflected as an underestimation of the estimated fetal weight. Study Design: A retrospective review of 225 abdominal circumference measurements made between 24 and 41 weeks of gestation in 85 fetuses with congenital diaphragmatic hernia was performed. The individual and mean abdominal circumference value at each week of gestation versus gestational age was plotted and compared with normative data. Comparisons between abdominal circumference measurements and hernia variables were made with the χ2 test. The Pearson correlation was used to examine the accuracy of ultrasonographic determination of the estimated fetal weight. Results: The mean measurements of abdominal circumference were not found to differ significantly from normative data until term, although fetuses with liver herniation were less likely to have measurements more than 2 standard deviations below the mean. Calculation of estimated fetal weight was similar in accuracy to that in normal fetuses. Conclusion: Small abdominal circumference measurements should not be expected in fetuses with congenital diaphragmatic hernia. Abnormalities of the abdominal circumference or an abdominal circumference–dependent estimated fetal weight should not be attributed to the anatomic defect without considering other etiologies. (Am J Obstet Gynecol 2002;186:321-4.)