Predicting Adverse Neonatal Outcome Especially When Gestational Age Is Uncertain: Utility of Sonographic Measurement of Fetal Abdominal Wall Thickness.

Early and accurate prenatal diagnosis of intrauterine growth restriction is important. Commonly used biometric parameters have limited specificity and require accurate dating. Fetal abdominal wall thickness (AWT) could be a useful supplemental parameter. We performed a retrospective study of 100 third trimester ultrasound exams and compared the sensitivity and specificity of AWT to those of weight percentile (WP) in predicting adverse perinatal outcome.There is a statistically significant difference between the AWT of patients with normal perinatal outcome and that of patients with adverse outcome (P < 0.01). When compared with WP across the entire range of the receiver operating characteristics curve, AWT [area under the curve (AUC), 0.76] has an efficacy similar to that of WP (AUC, 0.72; P = 0.30). However, AWT has superior performance over WP (AUC, 0.72 vs AUC, 0.61, respectively, P = 0.04) in the high specificity range (70%-100%) of the receiver operating characteristics curve, where the consequences of a false negative greatly outweigh those of a false positive. In our study population, with a cutoff value of 4 mm, AWT was a useful and more specific predictor of adverse perinatal outcome than WP. Abdominal wall thickness may be more useful in situations when dating is uncertain.